Radiation Physics Test 1 - Problems

Front 1

What is the energy of the photon whose momentum is equal to that of a 5 MeV electron?

Back 1

5.487 MeV

Front 2

Calculate the ratio v/c and m/m0
for a 2 MeV electron and a 1 MeV
proton.( v = speed of the particle)

Back 2

Electron:

v/c = .979

m/m0 = 4.91

Proton

v/c = 0.462

m/m0 = 1.001

Front 3

Two electrons are initially at rest, separated by 0.1 nm. After the electrons are released, they repel each other. What is the kinetic energy of each electron when they are 1 nm apart?

Back 3

6.48 eV

Front 4

(a) What is the kinetic energy of an electron whose velocity is 90% of the speed of light?

(b) How much additional energy is required
to increase the velocity of this electron to 99% of the speed of light?

(c) What is the mass of the electron in (b)?

Back 4

(a) 0.661 MeV

(b) 2.450 MeV

(c) 3.622 MeV/c^2

Front 5

Assume an uncertainty in the momentum of an electron is equal to one-half of its momentum. Calculate the uncertainty in position
of a 1 MeV electron.

Back 5

1.40 * 10^-13 m

Front 6

What is the wavelength of
(a) a 2 MeV neutron
(b) an electron whose kinetic energy is1000 eV ?
(c) a 10^−8 kg water droplet falling at the rate of 0.01 m/s ?

Back 6

(a) 2.02 * 10^-14 m

(b) 3.88 * 10^-11 m

(c) 6.626 * 10^-24 m

Front 7

What is the closest distance that a 4.0 MeV alpha particle can make a gold nucleus?

Back 7

5.69 * 10^-14 m

Front 8

Calculate the uncertainty in position of an electron that was accelerated across a potential difference 10^5 ± 100 V .

Back 8

5.41 * 10^-10 m

Front 9

A pi+ meson at rest decays into a μ+ meson and a neutrino in 2.5 × 10^−8 s. Assuming that the pi+ meson has kinetic energy equal to its rest energy. What distance would the meson travel before decaying as seen by an observer at rest?

Back 9

12.98 m

Front 10

Consider a symmetric elastic collision between a particle of mass m and kinetic energy T and a particle of the same mass at rest. Relativistically, show that the cosine of the angle between the two particles after the collision is T/(T+4mc^2)

Back 10

Conservation of energy, conservation of momentum

Front 11

A rod having a slope m relative to the x−axis of S, moves in the x direction at speed u. What is the rod’s slope in the usual second frame S'?

Back 11

m' = m = m/(sqrt(1-(v/c)^2))

Front 12

Find < x > and < x^2 > for the first excited state ( n = 2) in an infinite square-well potential.

Back 12

< x > = L/2

< x^2> = (1/3 - 1/(8*pi))L^2

Front 13

A particle of rest mass 1 MeV/c2 and kinetic energy 4 MeV collides with a stationary particle of rest mass 3 MeV/c2. After the collision, the two particle stick together. Find (a) the initial momentum of the system (b) the final velocity of the two-particle system, and (c) the rest mass of the two-particle system.

Back 13

(a) 4.889 MeV/c

(b) 0.612 c [v/c = pc/E]

(c) 6.36 MeV/c^2

Front 14

Two particles with the same mass m are emitted in the same direction, with momenta 10mc and 20mc respectively. As seen from the slower one what is the velocity of the faster particle, and vice
verse?

Back 14

0.599 c and -0.599 c

Front 15

A particle is in the ground state of an infinite square well potential. Find the probability of finding the particle (a) in the range 0 < x < L/4

(b) in Δx = 0.02L at x = L/2

Back 15

(a) 0.09808

(b) 0.0400

Front 16

How much energy is required to accelerate an electron from rest to a speed of 0.9c?

Back 16

0.66 MeV

Front 17

How fast must a particle move before its kinetic energy equals its rest energy?

Back 17

0.866c

Front 18

What is the factor of a proton accelerated to an energy of 20 TeV ?

Back 18

21,316

Front 19

A particle has a velocity u_x' = dx'/dt in S' frame which is moving at v along x' direction relative to S frame. The velocity of the particle measured in S frame is u_x. show that,
u_x = (u'+v)/(1+uv/c^2)

Back 19

Lorentz Transformations

Front 20

Two particles are aimed directly at each other. The first particle is moving at a speed of 0.8c to the right and the second particle is moving to the left at a speed of 0.7c. Assume both speeds are measured relative to the laboratory frame.
(a) Find the velocity of second particle relative to the first. (b) Find the velocity of first relative to the second.

Back 20

(a) -0.962

(b) 0.962

Front 21

Two particles with rest masses m1 and m2 move collinearly in some inertial frame, with uniform velocities u1 and u2, respectively. They collide and form a single particle with rest mass m moving at velocity u. Prove that

m^2 = m1^2 + m2^2 +

2*m1m2(u1)(u2)(1-u1u2/c^2)

Back 21

Conservation of energy

Conservation of momentum

Front 22

A meter stick is observed to be only 0.9 m long to an inertial observer. At what speed, relative to the observer, must the meter
3 stick be moving?
(a) 0.44 × 108 m/s (b) 0.57 × 108 m/s

(c) 0.95 × 108 m/s (d) 1.31 × 108 m/s

(e) 2.70 × 108 m/s

Back 22

D

Front 23

The temperature of a 5.00 kg lead brick is increased by 225 C0. If the specific heat capacity of lead is 128 J.kg−1C0−1 , what is the
increase in the mass of the lead brick when it has reached its final temperature?
(a) 4.80 × 10−4 kg (b)2.40 × 10−12 kg

(c) 1.60 × 10−12 kg (d) 9.66 × 10−11 kg

(e) 4.33 × 10−11 kg

Back 23

C

Front 24

The average power output of a nuclear power plant is 5.00 × 102 MW. In one minute, what is the change in the mass of the nuclear fuel due to the energy being taken from the reactor? (Assume 100% efficiency)
(a) 9.3 kg (b) 3.3 × 10−7 kg

(c) 3.3 × 10−13 kg (d) 9.3 × 10−11 kg

(e) 9.3 × 10−17 kg

Back 24

B

Front 25

The rest energies of three subatomic particles are:
Particle X: 107 MeV Particle Y:140 MeV Particle Z: 0.51 MeV Which one of the following statements is necessarily true concerning
these three particles?
(a) Particle Z, at rest, could decay into particle X and give off electromagnetic radiation.
(b) Particle X, at rest, could decay into particle Y and give off electromagnetic radiation.
(c) Particle X, at rest, could decay into particle Y and Z and give off electromagnetic radiation.
(d) Particle Y, at rest, could decay into particle X and Z and give off electromagnetic radiation.
(e) Particle Z, at rest, could decay into particle X and Y and give off electromagnetic radiation.

Back 25

D

Front 26

The starship Enterprise approaches the planet Risa at a speed of 0.8c relative to the planet. On the way, it overtakes the intergalactic freighter Astra. The relative speed of the two ships as measured by the navigator on the Enterprise is 0.5c. At what speed is Astra approaching the planet?
(a) 0.1c (b) 0.3c (c) 0.5c (d) 0.6c (e) 0.9c

Back 26

C

Front 27

A stationary 4 kg shell explodes in three pieces. Two of the fragments have a mass of 1 kg each and move along the paths shown with a speed of 10 m/s. The third fragment moves upward as
shown in the figure.What are the speed of the third fragment and the speed of the center of mass of this system after the explosion?

Back 27

v = 5 m/s

v_cm = 0 m/s

Front 28

A 0.015 kg marble moving to the right at 0.40 m/s has a head-on elastic collision with a 0.045 kg marble sitting at rest on a smooth, level surface. Which of the following are the correct magnitudes and directions of the velocities of the two marbles after the collision?

Back 28

v1 = -0.2

v2 = 0.045

Front 29

A 35 kg girl is standing near and to the left of a 43 kg boy on the frictionless surface of a frozen pond. The boy tosses a 0.75 kg ice ball to the girl with a horizontal speed of 6.2 m/s. What are the velocities of the boy and the girl immediately after the girl catches the ice ball?

Back 29

v_boy = 0.11 m/s

v_girl = -0.13 m/s

Front 30

The position of a hydrogen atom ( m = 1.7 × 10^−27 kg) is known to within 2.0 × 10−6 m. What is the minimum uncertainty in the atom’s velocity?
(a) 0.0085 ms−1 (b) 0.011 ms−1

(c) 0.015 ms−1 (d) 0.031 ms−1
(e) zero

Back 30

C

Front 31

The position of a 0.001 kg object moving in the x direction at 1 cm/s is known to within ±10 nm. In which range is the fractional uncertainty in the x component of its momentum?
(a) 10^−2 to 10^−4 (b) 10^−12 to 10^−14

(c) 10^−16 to 10^−18 (d) 10^−20 to 10^−22

(e) 10^−25 to 10^−30

Back 31

D

Front 32

A photon has a collision with a stationary electron ( h/mc = 2.43 × 10^−12m) and loses 5.0% its energy. The photon scattering angle is 180. What is the wavelength of the incident photon in this scattering process?
(a) 2.4 × 10−12 m (b) 4.6 × 10−11 m

(c) 9.2 × 10−11 m (d) 1.9 × 10−10 m

(e) 3.1 × 10−12 m

Back 32

C

Front 33

Photon of what minimum frequency are required to remove electrons from gold? The work function for gold is 4.8 eV .

(a) 7.3 × 10^14 Hz (b) 1.2 × 10^15 Hz

(c) 3.8 × 10^17 Hz (d) 6.5 × 10^15 Hz

(e) 4.6 × 10^14 Hz

Back 33

B

Front 34

The de Broglie wavelength of the matter wave associated with an electron accelerated by a voltage of 50 V is about,
(a) 100 Å (b) 10 Å (c) 1 Å (d) 0.1 Å (e) 10^−2 Å

Back 34

C

Front 35

Ba137 emits a gamma-ray photon of 0.66 MeV during an isomeric transition. Estimate the recoil kinetic energy of the atom in eV .
(a) 0.17 eV (b) 0.017 eV

(c) 17.0 eV (d) 170.0 eV

(e) 1.7 eV

Back 35

E

Front 36

How many degrees of freedom does a rigid body have?

Back 36

6

Front 37

The following set of counts readings was made in a gradient-free ray field, using a suitable detector for repetitive time periods of one minute: 18500; 18410; 18250; 18760; 18600; 18220; 18540; 18270; 18670; 18540.
(a) What is the mean value of the number of counts?
(b) What is its standard deviation (S.D)?
(c) What is the theoretical minimum S.D. of the mean?
(d) What is the actual S.D. of a single reading?
(e) What is the theoretical minimum S.D. of a single reading?

Back 37

(a) 18476

(b) 58.29

(c) 42.98

(d) 184.34

(c) 153.93

Front 38

A point source emits beta particles at a rate of 107 s^−1. What is the fluence density at a distance of 30 cm from the source?

Back 38

884.2 cm^-2 s^-1

Front 39

An ion exchange column contains radioactive materials that emits 5.5 × 10^5 cm^−1 of length. This column rests horizontally on the floor of a plant. Column is 9 m long and has a diameter of 5 cm. What is the unshielded fluence at a point 12 m away and 1 m above the floor?

Back 39

2.60*10^5 m^-2

Front 40

A solution of I (131) containing an activity of 107
s^−1 is spilled on an approximately circular area of 1 m in diameter. Determine the
fluence rate 10 m above the center of the contaminated area.

Back 40

7947.82 m^-2 s^-1

Front 41

A point source of Co (60) gamma rays emits equal numbers of photons of 1.17 and 1.33MeV , giving a flux density of 3.7×10^9 photons cm^−2 sec^−1 at a specified location. What is the energy flux density there, expressed in erg.cm^−2.s^−1 and in J.m^−2.min^−1?

Back 41

7411 erg cm^-2 s^-1

444.7 J m^-2 min^-1

Front 42

A 6 cm diameter pipe containing Co (60) with a lineal emission rate of 10^6 photons cm^−1s^−1 curves half-way around the ceiling of a circular
room of 10 m diameter. What is the flux 2.0 m below the pipe in the center of the room?

Back 42

4.31 * 10^6 m^-2 s^-1

Front 43

( Problem #08 on page 18 of Attix )
An X ray source at a point P contains 7.5×10^8 photons.m^−2.sec^−1.keV^ −1, uniformly distributed from 10 keV to 100 keV .
(a) What is the photon flux density at P?
(b) What would be the photon fluence in one hour?
(c) What is the corresponding energy fluence, in J.m−2 and erg.cm−2?

Back 43

(a) 6.75*10^10 m^-2 s^-1

(b) 2.43 * 10^14 m^-2

(c) 2.14 J m^-2 and 2.14 * 10^3 erg cm^-2

Front 44

Find
(a)the energy En of positronium
(b) the radius in relation to the radius of hydrogen
(c) the transition energies in relation to hydrogen

Back 44

(a) -∝^2*m_e*c/(4*n^2)

(b) 2*a_0

(c)E_H/2

Front 45

A hydrogen-like ion has the wavelength difference between the first lines of the Balmer and Lyman series equal to 16.58 nm. What
ion is it?

Back 45

Li 2+

Front 46

Use the uncertainty principle to estimate ground state energy of a two-electron atom of nuclear charge Ze.

Back 46

E = -(z-1/4)^2*27.2 eV

Front 47

Electrons have been removed from a beryllium atom (Z = 4) until only one remains. Determine the energy of the photon that can be emitted, if the remaining electron is in the n = 2 level.
(a) 13.6 eV (b) 54.4 eV

(c) 122.0 eV (d) 164.0 eV

(e) 218.0 eV

Back 47

D

Front 48

Which one of the following will result in an electron transition from the n = 4 level to n = 7 level in a hydrogen atom?
(a) emission of a 0.28 eV photon

(b) emission of a 0.57 eV photon
(c) emission of a 0.85 eV photon

(d) absorption of a 0.28 eV photon

(e) absorption of a 0.57 eV photon

Back 48

E

Front 49

A bullet of mass 40 gm travels at 1000 ms−1. What wavelength can we associate with it?
(a) 1.7 × 10−20 m (b) 1.7 × 10−30 m

(c) 1.7 × 10−35 m (d) 1.7 × 10−40 m

(e) 1.7 × 10−45 m

Back 49

C

Front 50

The wavelength of the first line of the Lyman series of a ten time ionized Na atom ( Z = 11) is about ( the first line of the Lyman series of hydrogen is 1216 Å )
(a) 0.1 Å (b) 10 Å (c) 1000 Å (d) 1.30 Å (e) 100 Å

Back 50

B

Front 51

The total number of electron states with n = 2, l = 1 for Hydrogen atom is
(a) 2 (b) 4 (c) 6 (d) 8 (e) 10

Back 51

C

Front 52

An electron in an atom has the following set of quantum numbers n = 3, l = 2,m_l = +1,m_s = +1/2
In which subshell can the electron be found?
(a) s (b) p (c) d (d) f (e) g

Back 52

C

Front 53

Of the following, the particle which most easily penetrates the nucleus of an atom is the,
(a) proton (b) alpha particle

(c) deuteron (d) electron

(e) neutron

Back 53

E

Front 54

Which one of the followings would constitute an inertial reference frame?
(a) A train rounding a turn with constant velocity
(b) an orbital space station
(c) A weather balloon descending with constant velocity
(d) a rotating merry-go-round
(e) a rocket undergoing uniform accelerating

Back 54

C

Front 55

Which one of the following statements is a consequence of special relativity?
(a) The length of a moving object is larger than it was at rest.
(b) Clocks that are moving run slower than when they are at rest
(c) Events occur at the same coordinates for observers in all inertial reference frames
(d) The speed of light has the same value for observers in all reference frames
(e) Events occur at the same time for observers in all inertial reference frames

Back 55

B

Front 56

Two helium-filled balloons are released simultaneously at points A and B on the x-axis in an earth-based reference frame. Which one
of the following statements is true for an observer moving in the +x direction?
(a) The observer always sees the balloons released simultaneously
(b) The observer sees balloon A released before balloon B
(c) The observer sees balloon B released before balloon A
(d) The observer can not determine whether they were released separately or simultaneously
(e) The observer could see either balloon released first depending on his speed and the distance to between A and B

Back 56

E

Front 57

The proper time between two events is measured by clocks at rest in a reference frame in which the two events:
(a) occur at the same place
(b) occur at the same time
(c) are separated by the distance a light signal can travel during the time interval
(d) occur in Durham
(e) satisfy none of the above

Back 57

A

Front 58

A meter stick moves at 0.95c in the direction of its length through a laboratory. According to measurements taken in the laboratory, its length is
(a) 0 (b) 0.098 m (c) 0.31 m (d) 3.2 m (e) 1.0 m

Back 58

C

Front 59

Observer A measures the relativistic velocity of a rocket as v and a comet as u. Here u and v are parallel and in the direction of observer’s positive x-axis. The speed of the comet as measured by an observer on the rocket is?

Back 59

(u-v)/(1-uv/c^2)

Front 60

An object A moving away from us at a speed of 0.8c. A second
object B is moving away from us in the opposite direction at a speed of 0.5c. The speed of A as measured by an observer on B is:
(a) 0.12c (b) 0.35c (c) 0.93c (d) 1.1c (e) 3.17c

Back 60

C

Front 61

A meson when at rest decays 2 μs after it is created. If moving in laboratory 0.99c, its lifetime according to laboratory clock would
be:
(a) the same (b) 0.28 μs
(c) 14 μs (d) 4.6 s
(e) none of the above

Back 61

C

Front 62

A mass of a particle is m. In order for its total energy to be twice its rest energy, its momentum must be?

Back 62

sqrt(3)*mc

Front 63

The units of h are those of:

(a) power (b) energy
(c) momentum (d) angular momentum
(e) frequency

Back 63

D

Front 64

The frequency of light beam A is twice that of light beam B. The ratio EA/EB of photon energies is:
(a) 4 (b) 2 (c) 1 (d) 14 (e) 12

Back 64

B

Front 65

In Compton scattering the frequency of the emitted light is independent of :
(a) the frequency of the incident light
(b) the speed of the electron
(c) the scattering angle
(d) the electron recoil energy
(e) none of the above

Back 65

E

Front 66

In Compton scattering from stationary electrons the largest change in wavelength that can occur is?

Back 66

4.85*10^-12 m

Front 67

Of the following, Compton scattering from electrons is most easily observed for:
(a) x rays
(b) ultraviolet rays
(c) visible light
(d) infrared light
(e) microwave

Back 67

A

Front 68

Which type of wave motion does not involve photon?
(a) sound waves
(b) x-rays
(c) gamma rays
(d) microwaves
(e) radio waves
(f) infrared radiation

Back 68

A

Front 69

The work function for a particular metal is 4.0 eV . Which one of the following best describes the wavelength of electromagnetic radiation needed to eject electrons from the metal?
(a) 310 nm or smaller
(b) 310 nm or greater
(c) 620 nm or greater
(d) 620 nm or smaller
(e) 800 nm or greater

Back 69

A

Front 70

Frame S’ moves in the x-direction at 0.6c with respect to frame S. A particle moves in the x direction at 0.4c as measured by an observer in S’. The speed of the particle as measured by an observer in S is?

Back 70

25c/31

Front 71

Which one of following is a consequence of the postulate of the special theory of relativity?
(a) There is no such thing as inertial reference frame
(b) Newton’s laws of motion apply in every reference frame
(c) Coulomb’s law of electrostatics applies in every frame
(d) The question of whether an object is at rest in the universe is
meaningless
(e) The value of every physical quantity

Back 71

D

Front 72

A particle of rest mass m moves with a speed 0.6c. Its kinetic energy is:
(a) 0.18mc^2
(b) 0.25mc^2
(c) 0.75mc^2
(d) mc^2
(e) 1.25mc^2

Back 72

B

Front 73

Which one of the following statements concerning the proper time interval between two events is true?
(a) It is value depends upon the speed of the observer
(b) It is value depends upon the choice of the reference frame
(c) It is the longest time interval that any observer can measure for the event
(d) It is the shortest time interval that any observer can measure for the event
(e) It is measured by the observer who is in motion with respect to the event

Back 73

D

Front 74

How much energy will be released if 1.0 g of material were completely converted into energy?

Back 74

9*10^13 J

Front 75

A laser emits pulse of light with energy 5 × 103 J Determine the number of photons in the pulse if the wavelength of the light is 480 nm

Back 75

1.2*10^22

Front 76

What is the de Broglie wavelength of an electron ( m = 9.11 × 10^−31 kg ) in a 5.0 × 10^3 V x-ray tube?

Back 76

0.017 nm

Front 77

A 2 MeV photon is scattered by a Compton interaction. What is the maximum energy transferred to the recoiled electron?

Back 77

?

Front 78

What is the angular momentum of the electron in the n = 5 state of the Hydrogen?

Back 78

5.27*10^-34 J*s

Front 79

Calculate the ionization potential of Li 2+

Back 79

122.4

Front 80

Calculate the radius of the n = 2 electron orbit in the Bohr hydrogen atom.

Back 80

5.29*10^-11 m (n^2/Z)

Front 81

Calculate the orbital radius for the n = 2 state of Li2+.

Back 81

5.29*10^-11 m (2^2/3)

Front 82

What are the energies of the photons with the two longest wavelengths in the Paschen series?

Back 82

1.51 m

Front 83

How many energy levels of the He+ ion lie below −1 eV ?

Back 83

7

Front 84

Calculate the current of the electron in the ground state of the hydrogen atom.

Back 84

1.05*10^-3 A

Front 85

Calculate the reduced mass of the He+ system.

Back 85

9.108*10^-31 kg

Front 86

What is the reduced mass of a system of two particles of equal mass, such as an electron and positron, orbiting about their center of mass?

Back 86

?

Front 87

Calculate the de Broglie wavelength of a 245 keV electron.

Back 87

2.23*10^-12 m

Front 88

How much energy is required to remove an electron from the n = 5 state of He+?

Back 88

?

Front 89

What is the momentum of a photon of lowest energy in the Balmer series of hydrogen?

Back 89

?

Front 90

How many electrons per second strike the target in an X-ray tube operating at current of 50 mA. (b) if the potential difference between the anode and cathode is 100 kV , how much power is expended?

Back 90

?

Front 91

The configuration of boron is 1s^2 2s^2 2p^1.
(a) How many electrons are in the L shell? (3)
(b) How many electrons have orbital quantum angular-momentum
number l = 0(4)?

Back 91

?

Front 92

What is incorrect in the electron configuration 1s^2 2s^2 2p^6 3s^2 3p^8 3d^10?

Back 92

?

Front 93

How much force acts on the electron in the ground state of the hydrogen atom?

Back 93

?

Front 94

The length of an uniform radioactive rod is L. Derive an expression for the fluence at a point P. The shortest distance to from the middle of the rod to P is x and assume the rate of emission of
gamma is N s−1.

Back 94

s_l/(4*pi*x)*2*tan^-1(L/(2x))

Front 95

The diagram shows a circular radioactive disc source with emission rate SA s^−1 and radius R. Derive an expression for the fluence
at the point P.

Back 95

S_A/(4*pi*R)*ln(1+R^2/x^2)

Front 96

A point source emits beta particles at a rate of 10^7 s^−1. What is the fluence density at a distance of 30 cm from the source?

Back 96

?

Front 97

Calculate the (a) fluence rate (b) energy fluence density from a 10^11 sec^−1, 137 Cs (0.662 MeV ) point source at a distance of 1.25 m.

Back 97

?

Front 98

Which one of the following will result in an electron transition from the n = 4 level to n = 7 level in a hydrogen atom?
(a) emission of a 0.28 eV photon (b) emission of a 0.57 eV photon (c) emission of a 0.85 eV photon (d) absorption of a 0.28 eV photon (e) absorption of a 0.57 eV photon

Back 98

?

Front 99

A bullet of mass 40 gm travels at 1000 ms−1. What wavelength can we associate with it?
(a) 1.7 × 10−20 m (b) 1.7 × 10−30 m

(c) 1.7 × 10−35 m (d) 1.7 × 10−40 m

(e) 1.7 × 10−45 m

Back 99

?

Front 100

The classical electron radius is of the order of
(a) 10^−8 cm (b) 10^−14 cm

(c) 10^−15 cm (d) 10^−10 cm

(e) 10^−13 cm

Back 100

E

Front 101

Electrons have been removed from a beryllium atom (Z = 4) until only one remains. Determine the energy of the photon that can be emitted if the remaining electron is in the n = 2 level.
(a) 218 eV (b) 200 eV
(c) 164 eV (d) 122 eV
(e) 54.4 eV (f) 13.6 eV
(g) 3.4 eV

Back 101

?

Front 102

Determine the wavelength of incident EM radiation required to cause an electron transition from n = 6 to n = 8 level in a hydrogen atom.
(a) 7.5 × 103 nm (b) 5.9 × 103 nm
(c) 4.0 × 103 nm (d) 3.4 × 103 nm
(e) 2.2 × 103 nm (f) 1.2 × 103 nm
(g) 0.5 × 103 nm

Back 102

?

Front 103

Which one of the following will result in an electron transition from the n = 4 level to n = 7 level in the hydrogen atom?
(a) emission of a 0.28 eV photon
(b) emission of a 0.57 eV photon
(c) emission of a 0.85 eV photon
(d) absorption of a 0.28 eV photon
(e) absorption of a 0.57 eV photon

Back 103

?

Front 104

The kinetic energy of the ground state electron in hydrogen is 13.6 eV . What is its potential energy?

Back 104

C

Front 105

An electron is in the ground state of a hydrogen atom. A photon is absorbed by the atom and the electron is excited to the n=2 level. What is the energy in eV of the photon?

Back 105

10.2 eV

Front 106

The electron in a hydrogen atom is in the n=3 state. What is(are) the possible value(s) for an emitted photon?
(a) 1.89 eV or12.09 eV
(b) 1.89 eV or13.6 eV
(c) 0.66 eV or13.6 eV
(d) 0.66 eV or12.09 eV
(e) 1.51 eV

Back 106

A

Front 107

Determine the maximum wavelength of incident radiation that can be used to remove the remaining electron from a singly ionized
helium [He+(Z = 2)]. Assume the electron is in the ground state.
(a) 54.4 nm (b) 50.3 nm (c) 45.6 nm
(d) 35.6 nm (e) 22.8 nm (f) 12.4 nm
(g) 6.2 nm

Back 107

A

Front 108

An x-ray beam produced at 200 kVp has a Half Value Layer of 1.5 mm Cu. (a) What are the coefficient of linear and mass attenuation coefficients?

Back 108

0.46 mm^-1

0.52 cm^2/g

Front 109

A narrow beam containing 2000 monoenergetic photons is reduced to 1000 photons by a slab of copper 1 cm thick. (a) What is the total linear attenuation coefficient of the copper slab for these photons? (b) What are the mass, atomic and electronic attenuation coefficients of the copper slab? ( copper density = 8.9 gmcm−3). (c) To the 1 cm copper slab, 2 cm of copper are added. How many photons remain in the beam emerging from the slab?

Back 109

(a) 0.693 cm^-1

(b) 0.0779 cm^2 g^-1, 8.23*10^-24 cm^2 atom^-1,

2.84*10^-25 cm^2 electrons^-1

(c) 250

Front 110

The photon flux density is 10^9 photons m^−2 sec^−1 for a beam of rays. One fourth of the photons have an energy of 500 keV and three fourth of the photons have an energy of 1.25 MeV . What is the energy flux density of the beam?

Back 110

1.06*10^9 MeV s^-1

Front 111

A sphere and a cylinder start from rest at the same position and roll down the same incline.
(a) The cylinder will reach the bottom first and is independent of the mass and radius of the two objects.
(b) Which one reaches the bottom first will depend on the mass of the object.
(c)They will reach the bottom at the same time and are independent of the
mass and radius of the two object.
(d) Which one reaches the bottom first will depend on the radius of the object.
(e) The sphere will reach the bottom first and is independent of the mass and
radius of the two objects.

Back 111

E

Front 112

As white light enters a lens it undergoes a change in
(a) wave length only
(b) velocity only
(c) frequency only
(d) wave length and velocity
(e) none of the above

Back 112

D

Front 113

The Pauli exclusion principle states that
(a) particles with integer and half integer spin cannot exist in same state
(b) particles with integer spin cannot exist in same state
(c) particles with integer spin can exist in same state
(d) particles with half integer spin can exist in same state
(e) particles with half integer spin cannot exist in same state

Back 113

E

Front 114

The moon revolves about the earth making a complete revolution in 27.3 days. Assume that the orbit is circular and has a radius of 385 × 10^6 meters. The magnitude of the acceleration of the moon toward the earth is about
(a) 2.8 × 10^−6 g
(b) 2.8 × 10^−5 g
(c) 2.8 × 10^−4 g
(d) 2.8 × 10^−2 g
(e) 2.8g

Back 114

C

Front 115

A sub-atomic particle traveling at a constant speed of 6 × 10^6 m/s enters a region of an electric field where it is decelerated at the rate of 1.2 × 10^14 m/s^2. The linear distance the particle travels before coming to rest is,
(a) 5 × 10−6 cm
(b) 30 × 10−2 cm
(c) 2 cm
(d) 15 cm
(e) 15 × 10−2 cm

Back 115

?

Front 116

Electrons have been removed from a Beryllium atom (Z = 4) until only one remains. Determine the energy of the photon that can be emitted if the remaining electron is in the n = 2 level.
(a) 13.6 eV (b) 54.4 eV (c) 122.0 eV

(d) 164.0 eV (e) 218.0 eV

Back 116

D

Front 117

If the absolute value of the wave function of a proton is twice as large at location A than at location B, how many times is it more likely to find the proton in location A than in B?
(a) 4 (b) 2 (c) 1 (d) 0.5 (e) 0.25

Back 117

A

Front 118

Why was it necessary for Bohr to require that electrons remain in stationary orbits?
(a) An electron must travel in a circular orbit.
(b) It was required by the Heisenberg uncertainty principle.
(c) No two electrons can be in the same region in the atom.
(d) It was required by the Pauli exclusion principle.
(e) Classical physics predicts that the electrons should spiral into the nucleus .

Back 118

E

Front 119

The total number of electron states with n = 2, l = 1 for hydrogen atom is
(a) 2 (b) 4 (c) 6 (d) 8 (e) 10

Back 119

C

Front 120

At what speed is a particle traveling, if its kinetic energy is three times its rest energy?
(a) 0.879c (b) 0.918c (c) 0.943c

(d) 0.968c (e) 0.989c

Back 120

D

Front 121

What are the possible values of n and m if (a) l = 3 and (b) l = 0?

Back 121

(a) n = 4,5,6,... m = -3,-2,...2,3

(b) n = 1,2,3,... m = 0

Front 122

The wavelength of the K_a line in iron (Z = 26) is known to be 193 pm. Then what would be the wavelength of the K_a line for copper (Z = 29)?

Back 122

153.8 pm

Front 123

rocket moving at 0.500c relative to some inertial observer fires a missile at a speed of 0.300c (as measured by the rocket pilot) in the direction of the rocket velocity. What can you say about the missile’s velocity relative to the inertial observer?
(a) it is 0.800c
(b) it is more than 0.800c
(c) it is less than 0.800c
(d) it is greater than c

Back 123

C

Front 124

Which particle has the greatest speed?
(a) an electron with a total energy of 1000 MeV
(b) a proton with a total energy of 1000 MeV
(c) a neutron with a total energy of 1500 MeV

Back 124

A

Front 125

A proton and an electron have the same kinetic energy and are moving at speeds much less than the speed of light. The ratio of De Broglie wave length of the electron to that of proton is?

Back 125

sqrt(m_e/m_p)

Front 126

The ground state electronic configuration of a neon atom is 1s^2 2s^2 2p^6. How many of these electrons have magnetic quantum number m_l = 0?

Back 126

C

Front 127

A beam of 4.5 MeV neutrons is directed at a 0.030 kg tissue sample. Each second, 1.5 × 10^6 neutrons strike the sample. If the RBE of these neutrons is 7.0, what biological equivalent dose is received by the sample in 65 seconds?
(a) 0.23 rem (b) 0.55 rem (c) 1.6 rem (d) 19 rem (e) 33 rem

Back 127

?

Front 128

The figure shows an energy level diagram for the hydrogen atom. Several transitions are shown and labeled by letters. Determine the wavelength of the radiation involved in transition B.

Back 128

?

Front 129

A photon in light beam A has twice the energy of a photon in light beam B. The ratio P_A/P_B
of their momenta is:

(a) 1/2 (b) 1/4 (c) 1 (d) 2 (e) 4

Back 129

?

Front 130

The absorption coefficient of aluminum is 0.73 cm^−1 for X rays of wavelength 0.20 A and the density of aluminum is 2.1 g.cm^−3. The mass absorption coefficient is:
(a) 0.345 cm^2.g (b) 2.70 cm^2.g

(c) 1.5 cm^2.g (d) 0.15 cm^2.g

(e) 0.73 cm^2.g

Back 130

?

Front 131

Find the orbital radius and energy of an electron in a hydrogen atom characterized by the principal quantum number n = 3.
(a) 0.476 nm,−1.51 eV (b) 0.0529 nm,−1.51 eV

(c) 0.476 nm,−1.51 eV (d) 0.476 nm,−13.6 eV

(e) 0.0529 nm,−13.6 eV

Back 131

?

Front 132

If the uncertainty in the position of a moving particle increases,
(a) the particle may be located more exactly.
(b) the uncertainty in its momentum decreases,
(c) the uncertainty in its speed increases,
(d) the time to measure the position increases

Back 132

?

Front 133

Which color of photons will have the least momentum?
(a) red (b)green (c) violet (d)yellow

Back 133

?

Front 134

What is the minimum potential difference that must be applied to an X ray tube to knock a K shell electron completely out of an atom in a copper (Z = 29) target?
(a) 9.20 × 10^3 V (b) 1.47 × 10^4 V

(c) 1.07 × 10^4 V (d) 1.30 × 10^4 V
(e) 1.24 × 10^4 V

Back 134

?

Front 135

In the Compton effect, a photon of wavelength and frequency f hits an electron that is initially at rest. Which one of the following occurs as a result of the collision?
(a)The photon is absorbed completely.
(b) The photon gains energy, so the final photon has a frequency greater than f
(c) The photon gains energy, so the final photon has a wavelength greater than λ
(d) The photon losses energy, so the final photon has a frequency less than f.
(e) The photon losses energy, so the final photon has a wavelength less than λ

Back 135

?

Front 136

Which one of the following electronic configuration corresponds to an atomic
ground state?
(a) 1s^2 2s^1 2p^6 (b)1s^1 2s^1 2p^1

(c)1s^1 2s^2 3p^1 (d)1s^2 2s^2 2p^1

(e)1s^1 2s^2 2p^1

Back 136

D

Front 137

Calculate the K X ray wavelength for a gold atom (Z = 79).
(a) 5.13 × 10^−10 m (b) 8.54 × 10^−10 m

(c) 2.00 × 10^−11 m (d) 3.60 × 10^−11 m

(e) 2.47 × 10^−13 m

Back 137

?

Front 138

A photon source emits photons of 1.50 MeV giving a flux density of 2.3 × 10^8 photons.cm−2.sec−1 at a specified location. What is the energy flux density at this location?

(a) 5.53×10^−5 J.cm^−2.s^−1

(b) 5.53×10^−11 J.cm^−2.s^−1

(c) 3.45×10^8 J.cm^−2.s^−1

(d) 5.53 × 10^8 J.cm^−2.s^−1

(e) none of the above

Back 138

?

Front 139

The total energy E of a free moving particle of mass m with speed v is given
by which of the following?

Back 139

?

Front 140

What are the values of (Rin)_u, (Rout)nonr_u , (R)r_u, (Rout)_c, (Rout)_u, sum(Q )for the given volume?

Back 140

(Rin)_u = hv_1+hv_2

(Rout)nonr_u = hv_5+hv_6

(R)r_u = hv_3+hv_4

(Rout)_c = T_1+T_2

sum(Q ) = 0

Front 141

A fluence, differential in energy has the form
φ'(E) = N/E^2 Emin <= E=> Emax and zero everywhere else. Where N is a constant.
(a) What is the total fluence?
(b) What is the energy fluence, differential in energy?
(c) What is the total energy fluence?

Back 141

(a) N*[1/Emin-1/Emax]

(b) N/E

(c) N*ln(Emax/Emin)

Front 142

The flux density of 5 MeV gamma rays is 3.0 × 10^6 cm^−2s^−1 at a point in Pb. What are the the kerma and collision kerma after one hour?
(Given: (μ/p) = 0.0436 cm^2g^−1, (μ_tr/p) = 0.0331 cm^2g^−1, (μen/p) = 0.0272 cm^2g^−1)

Back 142

?

Front 143

Calculate the Kerma, collision Kerma, and absorbed dose in spherical volume of
interest in each of two cases in figure given below. Assume mass of each volume
is 10 g.

Back 143

Front 144

At a depth of 47 cm in a medium the absorbed dose is found to be 3.95 Gy, while that resulting only from primary radiation is 3.40 Gy. At the front surface of the medium, the dose from primary radiation is 10.0 Gy. Calculate the followings: ( Assume CPE and plane, monoenergetic primaries.)
• the dose buildup factor B
• the linear attenuation coefficient
• the mean effective attenuation coefficient

Back 144

?

Front 145

Consider a beam of 3 MeV rays perpendicularly incident on an Fe foil that is very thin in comparison with the range of the secondary electrons.
• What are the values of K,Kc and Kr in the foil for a fluence of 5.6 × 10^15 photons per m^−2. (Given μtr/p = 0.00212 m^2 g^−1 and μen/p = 0.00204 m^2 g^−1)
• What is the absorbed dose in the foil, assuming no charged particles are
incident from elsewhere?
• What would happen to K,Kc,Kr and D if a strong magnetic field were
applied with the lines of force lying in the foil?

Back 145

?

Front 146

In the electronic configuration 1s^2 2s^2 2p^6 the number of electrons having l = 1 is?

Back 146

6

Front 147

The electron in a hydrogen atom is in a state with l= 5. The minimum angle between L and the z-axis is?

Back 147

24.1

Front 148

The figure above shows a plot of the time- dependent force F_x(t) acting on a particle in motion along the x-axis. What is the total impulse delivered to the particle?

Back 148

2 kg m/s

Front 149

The momentum of an electron is 1.60 times larger than the value computed non-relativistically. What is the speed of the electron?

Back 149

2.34E+08 m/s

Front 150

In the hydrogen spectrum, the ratio of the wavelengths for Lyman- radiation (n = 2 to n = 1) to Balmer- radiation (n = 3 to n = 2) is?

Back 150

5/27

Front 151

An astronomer on earth observes two galaxies moving away from each other along a line that passes through the earth. The astronomer finds that each is moving with a speed of 2.1E+8 m/s relative to the earth. At what speed are the galaxies moving apart relative to each other?

Back 151

2.8E+8 m/s

Front 152

n the production of X rays, the term
“bremsstrahlung” refers to which of the
following?

(a) The cut-off wavelength, , of the X-ray tube

(b) The discrete X-ray lines absorbed when an
electron in an inner orbit fills a vacancy in
an outer orbit of the atoms in the target
metal of the X-ray tube

(c) The smooth, continuous X-ray spectra
produced by high-energy blackbody
radiation from the X-ray tube

(d) The smooth, continuous X-ray spectra
produced by rapidly decelerating electrons
in the target metal of the X-ray tube

(e) The discrete X-ray lines emitted when an
electron in an outer orbit fills a vacancy in
an inner orbit of the atoms in the target
metal of the X-ray tube

Back 152

D

Front 153

Figure shows a 2.50 MeV photon that undergoes a Compton interaction at point A in the volume V.The kinetic energy of the Compton electron is 1.10 MeV . At point B, electron ejects a bremsstrahlung photon with energy 0.60 MeV. It spends the rest of the energy along the track BC and stops at C.
What are the values of , and (Rout)u ?

Back 153

1.4 MeV, 0.6 MeV, and 2.0 MeV

Front 154

A 10 MeV gamma ray enters a volume V and undergoes pair production, thereby disappearing and giving rise to an electron and positron of equal energies. The electron spends half of its kinetic energy in collision interactions before escaping from V. The positron spends half of its kinetic energy in collisions in V before annihilated in flight. The resulting photons escape from V. What are the energies of particles escaped from V? (Assume two equal photons and an electron)

Back 154

1.633 MeV photon, 1.633 MeV photon and 2.245 MeV electron

Front 155

Calculate the probability that a 2 MeV photon in a narrow collimated beam will be removed from the beam by Lead of 1.0 cm thick. ( linear attenuation coefficient for lead : µPb = 0.516 cm^-1 )

Back 155

0.403