Gcse Physics - P4 Radiation For Life

Front 1

Static Electricity

Back 1

Charges which are not free to move, causing them to build up in one place. When they finally move, it results in a spark

Front 2

Attraction of dust

Back 2

Dust particles are charged, so they'll be attracted to anything of the opposite charge.

Front 3

Preventing sparks

Back 3

Connecting a charged object to the ground using a conductor is called earthing. It provides an easy route for the static charge to travel into the ground.

Anti-static sprays work by making the charged object conductive. It provides and easy path for the charge to move away

Anti-static cloths are conductive, they carry charges away

Insulating mats and soles prevent static electricity from moving through them

Front 4

Dust precipitator

Back 4

1. Smoke particles encounter negatively charged wire grid at the bottom of the chimney, they become negatively charged

2. The dust particles then induce a charge on the earthed metal plates - The negatively charged dust repels electrons on the plate

3. Dust particles are attracted to the metal plates, where they form a larger particle

4. When heavy enough they fall off, to be removed later

Front 5

Current

Back 5

The flow of electrical charge around a circuit. Measured in amps, A. Current only flows through a component if there is a voltage across it.

Front 6

Voltage

Back 6

The driving force that pushes current around, measures in volts, V.

Front 7

Resistance

Back 7

Anything in the circuit which slows the flow down, measured in ohms.

Front 8

Plug wires

Back 8

Live wire - Carries the voltage, it's brown

Neutral wire - Completes the circuit, it's blue

Earth wire (and fuse) - For safety

Front 9

Formula for electrical power

Back 9

Power = Voltage × Current

Front 10

Formula for Resistance

Back 10

Resistance = Voltage ÷ Current

Front 11

Longitudinal waves

Back 11

The vibrations are along the same direction as the wave is travelling.

E.g sound

Front 12

Transverse waves

Back 12

The vibrations are perpendicular to the direction of travel of the wave.

Front 13

Ultrasound

Back 13

Ultrasounds are sound with a frequency of above 20,000 Hz, above the range of human hearing.

Front 14

Ultrasound applications

Back 14

-Breaking down kidney stones

-Body scanning

-Imaging soft tissues

Front 15

Alpha Radiation

Back 15

Alpha particle is made up of 2 protons and 2 neutrons (a helium nucleus). Its mass is 4 and its charge is +2. It forms a new element since 2 protons are emitted.

Front 16

Beta Radiation

Back 16

A beta particles is a fast-moving electron. It has no mass and a charge of -1. It loses a neutron but gains a proton. It forms a new element.

Front 17

Measure of radioactivity

Back 17

Radioactivity is measured in becquerels (Bq) or counts per minute (cpm). 1 Bq is 1 decay emitted per second.

Front 18

Half-Life

Back 18

Half-Life is the time taken for half of the radioactive nuclei now present to decay.

Front 19

Radioactive Dating

Back 19

By measuring the amount of radioactive isotope left ina sample, and knowing its half-life, you can work out how long the thing has been around.

Front 20

Nuclear Fission

Back 20

Nuclear fission is where uranium or plutonium split up to produce energy in the form of heat

Front 21

How are the chain reaction in nuclear fission controlled?

Back 21

Control rods usually made from boron absorb free neutrons.

Front 22

Nuclear Fusion

Back 22

2 light nuclei combine to create a larger nucleus. Fusion releases more energy than fission. The problem is, it only happens at high pressure and temperature (10,000,000 °C). It takes more power to reach such a high temperature than the generator would produce.