Paper 2

Question 1

Simple Harmonic Motion

Answer 1

Motion where acceleration is proportional to displacement and acting towards the equilibrium

Question 2

Diffraction

Answer 2

The spreading out of waves as they pass through gaps or around objects. It occurs significantly when the size of the gap is similar in size to the wavelength of the wave

Question 3

Describe how distances too large for the use of standard candles can be determined

Answer 3

• Measure change in wavelength/frequency
• Determine relative velocity using red shift equation
• Use v=H0 d

Question 4

Explain how fusion and fission both release energy.

Answer 4

• Fusion involves an increase in binding energy as the number of nucleons increases
• Fission involves an increase in binding energy as the number of nucleons decreases
• If binding energy per nucleon increases, energy is released in the process

Question 5

Absorption Spectrum

Answer 5

• Atoms have discrete energy levels
• Electrons get excited by absorbing photons
• Energy of photon absorbed = difference in energy levels
• Only certain transitions possible, so only certain photon energies absorbed so only certain frequencies missing
• The set of frequencies absorbed depends on the element

Question 6

Photoelectric effect

Answer 6

• Photon energy E=hf
• Photon energy must be greater than work function for metal to provide enough energy for photoemission OR frequency must be greater than or equal to threshold frequency
• One photon interacts with one electron
• With larger area, more photons are absorbed in a given time. Or light with greater intensity supplies more photons per second
• So more electrons are emitted in a given time

Question 7

Explain how a standing wave is formed.

Answer 7

• Superposition/interference between waves travelling in opposite directions
• At nodes the waves are in antiphase, so there is destructive interference. OR At antinodes the waves are in phase, so there is constructive interference
• At antinodes there is maximum amplitude OR At nodes there is zero amplitude

Question 8

Properties of lens between F1 and F2

Answer 8

Real
Inverted
Magnified

Question 9

Properties of lens at F2

Answer 9

Real
Inverted
No magnification/Same size

Question 10

Properties of lens at greater than F2

Answer 10

Real
Inverted
Diminished

Question 11

Properties of lens between F1 and lens

Answer 11

Virtual
Upright
Magnified