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11 Cards in this Set
- Front
- Back
- 3rd side (hint)
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18.2A plate carries a charge of -3.16mC, while a rod carries a charge of +1.90mC. How many electrons must be transferred from the plate to the rod, so that both objects have the same charge.
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1.58E13 electrons
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1.Figure out the difference between the charges. Divide by 2. This is Q.
2. Use Q=N(qe-). qe-=1.6E-19 C. 3.(Q/qe-)=N. Answer must be positive. |
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18.3
A metal sphere has a charge of +8.14mC. What is the net charge after 6.17E+13 electrons have been placed on it? |
-1.73 uC
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1.Use Q=N(qe) to figure out charge of electrons.
2.Subtract from original positive charge of object. |
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A charge of -2.92 mC is fixed at the center of a compass. Two additional charges are fixed on the circle of the compass (radius = 0.100 m). The charges on the circle are -3.94 mC at the position due north and +4.96 mC at the position due east. What is the magnitude of the net electrostatic force acting on the charge at the center?
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16.63 N
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1.Use F=k[(q_1/q_2)/r^2 to find the force vectors (y=10.3, x=13.02)
2.do the pythag thing 3.good |
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18.14
Two tiny conducting spheres are identical and carry charges of -19.6 mC and +49.8 mC. They are separated by a distance of 2.54 cm. What is the magnitude of the force that each sphere experiences? |
13601 N
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Use F=(k(q_1*q_2))/r^2
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18.28
Four point charges have the same magnitude of 2.13 x 10-12 C and are fixed to the corners of a square that is 4.17 cm on a side. Three of the charges are positive and one is negative. Determine the magnitude of the net electric field that exists at the center of this square? |
44.05 N/C
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(page p3 in problem notebook)
1.use horizontal, vertical distances to sides to determine net distance from inner point to charge (0.02949 m) 2.figure out if anything cancels by imagining a positive charge placed in the shape with only a single of the charges to be compared (i.e. with two positive, two negative charges on a square, a positive charge on the upper left will make the charge in the middle go down and to the right). In this problem, two of the charges cancel out. 3.In this case, use E_net=2(kq/r^2) b/c both forces are identical, no need to make messy |
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18.36
Two parallel plate capacitors have circular plates. The magnitude of the charge on these plates is the same. However, the electric field between the plates of the first capacitor is 2.36 x 105 N/C, while the field within the second capacitor is 3.60 x 105 N/C. Determine the ratio r2/r1 of the plate radius for the second capacitor to the plate radius for the first capacitor |
.8097
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1.Use E=((Q/A/E_o)), set up these equations for E_1/E_2, find out that E_1/E2=A_2/A_1. then sqrrt answer (.6556) since area of a circle is pir^2, pir^2_2/Pir^2_1, pi cancels out, so just square root it, get ratio.
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A spherical surface completely surrounds a collection of charges. Find the electric flux through the surface if the collection consists of a single +3.56E-6 C charge.
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402078.1568 N*m^2/C
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net charge/E_o (E_o is 8.854E-12)
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units for flux
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N*m^2/C
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58.
At a distance r1 from a point charge, the magnitude of the electric field created by the charge is 238 N/C. At a distance r2 from the charge, the field has a magnitude of 115 N/C. Calculate the ratio r2/r1. |
1.4385
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Use same approach as 36. Divide E_1/E_2 which equals A_2/A_1, square root answer.
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60.
In a vacuum, two particles have charges of q1 and q2, where q1 = +3.52 mC. They are separated by a distance of 0.294 m, and particle 1 experiences an attractive force of 3.27 N. What is the magnitude of q2? |
8.93×10-6 C
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use F=k(q1q2)/r^2, solve for q2
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A charge of q = +7.17 mC is located in an electric field. The x and y components of the electric field are Ex = 6.22E+3 N/C and Ey = 8.02E+3 N/C, respectively. What is the magnitude of the force on the charge?
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7.28×10-2 N
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Use pythag to find net energy of field, then use F=qEnet to find force
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