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Question 1

Why relativistic effects are ignored when (v/c) is less than 0.1

Answer 1

Lorentz factor is approximately equal to 1

Negligible change in length/time/mass observed

Question 2

What is meant by big bang theory

Answer 2

Universe initially in a hot / very dense state and then expanded

Question 3

Explain what is meant by length contraction

Answer 3

Decrease in length (In the direction of motion) of an object moving relative to an observer

Question 4

Reading on Newton Balance

Answer 4

F= Total Mass X A
A= f/m
Opposite side of force 
F= MA
F= Answer

Question 5

Explain what is the resultant force

Answer 5

Single force which has the same effect as all the others

Question 6

Why might an object move upwards

Answer 6

Vertical component of force exerted by eg parachute is greater than weight down

Question 7

What does a particle accelerator use to accelerate?

Deflect?

Answer 7

Electric fields to accelerate

Magnetic fields to deflect

Question 8

Changing the irradiance has no effect on frequency because

Answer 8

Max velocity is the same
One photon releases one electron
Each photon has same energy as before

Question 9

Determining whether constructive or destructive interference has occurred

Answer 9

Path difference
Number of wavelengths = Path difference/wavelength
Constructive for whole number/Destructive for half

Question 10

Larger refractive index means

Answer 10

Larger change in speed

Question 11

Possible changes to an experiment

Answer 11

Changing an independent variable eg

Length, thickness, material, colour/wavelength of light

Question 12

Graph of force/time for softer ball

Answer 12

Will have smaller force over a longer time

Question 13

Graph of force/time for softer ball

Answer 13

Will have smaller force over a longer time

Question 14

Why do dark lines occur in the Suns upper/outer atmosphere?

Answer 14

Photons of certain frequency are absorbed in the Suns upper/outer atmosphere

Question 15

Why do lines appear differently on different spectra?

Answer 15

Light is redshifted/shifted towards red end as galaxies are moving away (from eg sun)

Question 16

How can varying line emission spectra show expanding universe?

Answer 16

Redshift is greater for distant galaxy meaning it is moving away faster than the nearby one

Question 17

Comparing 10^-25 with 10^-27

Answer 17

10^-25 is two orders of magnitude greater

Question 18

Why is mass after a decay less than before the decay

Answer 18

Some mass is converted into energy

Question 19

What particle physicists suggest to make up for lost energy in a decay

Answer 19

An extra particle, the anti neutrino would have some kinetic energy

Question 20

Explain how an LED works

Answer 20

When a current passes through a P-n junction photons are emitted

Question 21

How to carry out experiment differently next time

Answer 21

Set variable eg speed differently and repeat for different speeds

Question 22

Finding the number of electrons passing between a plate in one minute

Answer 22

Q=IT where T is 60 secs

Number = Q/Charge on one electron

Question 23

Establishing relationship between irradiance and distance

Answer 23

K= I X D^2

Question 24

Why is a spectrum of light produced when a white light Ray is used

Answer 24

Each colour/frequency has a different refractive index and therefore the angle in air is different for each colour

Question 25

Every antiparticle

Answer 25

Has a corresponding elementary particle

The same mass as its equivalent particle

Question 26

An increase in irradiance will

Answer 26

Maintain kinetic energy

Increase number of photo electrons emitted each second

Question 27

Distance is greater in frame of reference of

Time is greater in frame of reference of

Answer 27

Earth observer for both

Question 28

Why spectrum lines are redshifted for a distant star/galaxy

Answer 28

The star is moving away from Earth

Light from the star is experiencing a Doppler shift

Question 29

Why there is an increase in length between tubes on a linear accelerator?

Answer 29

As proton speed increases they travel further each time

Question 30

The prism and grating

Answer 30

Produces a spectrum by refraction, grating produces a spectrum by interference
Prism produces a single spectrum
Grating produces more than one spectrum