Paper 1 revison

Question 1

What is meant by the rest energy of a particle?

Answer 1

Energy equivalent of the mass of the particle when it’s at rest/has 0 Ek

Question 2

An electron and positron collide with each other, each carrying a kinetic energy of 0.340 MeV at the time of collision. What happens? (rest mass of electron = 0.511 meV)

Answer 2

The particles collide, and annihilation occurs, releasing energy in the form of two gamma ray photons, each carrying an energy of 0.852MeV. The sum of the energy of the gamma ray photons is the sum of the total energy of the particles

Question 3

During beta decay, where does the beta particle come from?

Answer 3

A neutron decays to form a proton, electron and electron anti neutrino

Question 4

What is the center value of the diffraction grating pattern called? What is the one one space directly above/below?

Answer 4

zeroth order, first order

Question 5

On a diffraction grating pattern, if there are more maxima observed on the screen, what does this mean? what could cause this?

Answer 5

There is less diffraction due to a:
* smaller angle
* lower wavelength

Observations:
* distance between maxima decreased will be observed
* colour changes towards blue end of spectrum

Question 6

What is the law of conservation of momentum?

Answer 6

Before and after a collision momentum is conserved within a closed system

Question 7

What is the upwards force that acts on a plane in the air?

Answer 7

Lift, not upthrust as upthrust is only in fluids

Question 8

Why are superconductors used in electromagnets?

Answer 8

They can sustain large currents without thermal energy losses, and hence can generate large magnetic fields

Question 9

Why are gas atoms ionised when an electron beam is passed through the gas?

Answer 9

The electrons in the beam collide with the gas atoms transferring kinetic energy. This causes the electrons to be emitted from the atom, so the atom loses electrons to be ionised

Question 10

What is the formula for power?

Answer 10

P = Fv

Question 11

During beta minus decay, what is the change in quark structure?

Answer 11

Down to Up

Question 12

During beta plus decay, what is the change in quark structure?

Answer 12

up to down

Question 13

What is the difference between absorption and emission spectra?

Answer 13

Absorption spectra shows the wavelength of photons that have been absorbed by electrons to be excited to higher energy levels

Emission spectra show the wavelengths of photons that have emitted photons to de-excite to lower energy levels.

The energy levels are discrete

Question 14

Given two vectors how do you find the resultant?

Answer 14

join the tail of one vector to the top of the other, measure the distance between