exam revision

Question 1

Two uses of ultraviolet

Answer 1

Killing bacteria such as water purification

to decet counterfeiting of money

Question 2

Two dangers ultraviolet

Answer 2

Cell damage
Sunburn
Eyedamghe

Question 3

What is the charge of a alpha particle

Answer 3

2+

Question 4

What is the charge of of particle beta

Answer 4

-1

Question 5

Suggest why alpha radiation is more iosnisinhg than beta or gamma radiation?

Answer 5

Charge is larger and mass is larger

Question 6

Why is doctor reading never constant (radioactivity)

Answer 6

Radioactivity is random

Question 7

Explain why radioactivity sample reduces with time?

Answer 7

The activity is due to the nucleus decaying and after some time they are fewer radioactive nuclei

Question 8

Decrease how a teacher could measure the activity of a radioactive source?

Answer 8

Use a geiger counter to measure the background radiation, the teacher should wear gloves and control the experiment by putting the source near the detector. Should repeat and find average. Measure answer in Bq

Question 9

Explain how to use radioactive to find age of rock?

Answer 9

There is a know proportion
Measure the proportion of the activity now
Compare the activity to the original activity
Hence determine the number of half-lives elapsed

Question 10

What is the maximum range of beta particle

Answer 10

50CM

Question 11

How nuclear fission leads to a chain reaction:

Answer 11

Nucleus splits
Reralsing neutrons
Which hit different uranium nuclei

Question 12

Explain form that this energy takes nucleus fission

Answer 12

Kinetic energy of particles of fission products

Question 13

wave speed frequency and wavelength

Answer 13

wave speed = frequency x wavelength

Question 14

time period frequency

Answer 14

frquecny = 1/time period

Question 15

sin I sin r and n

Answer 15

n = sin I/sin r

Question 16

sin c and n

Answer 16

sin c = 1/n

Question 17

exam experiment speed of sound

Answer 17

speed = distance divided by time

stand 50m away from the wall and time how long it takes for the echo to come back

time how long it takes the echo to come back

repeat the experiment three times and find averages

Question 18

Thermal velocity

Answer 18

When an object falls its weight causes it to accelerate towards the ground.
Resistive forces act on it in the opposite direction to its motion.
As the object speed increase the resistive force increases until these balance the downwards force of the objects weight
So there is no resultant force so it travels at a constant

Question 19

what is the relationship between frequency of sound wave and the pitch of the sound

Answer 19

the higher the frequency the higher the pitch

Question 20

earth wire

Answer 20

there is a current in the wire so it discharges the object

Question 21

experiment charge testor

Answer 21

deflect gold leaf electroscope

Question 22

why does charge remain

Answer 22

there is insulation

Question 23

Hooke law

Answer 23

until the elastic limit extension is directly proportional to force