1.
State what is meant by phase difference.
[1 mark]
- how far out of step two waves are
JD SCIENCE
Electricity and waves
Indicative marking points. Award marks for equivalent scientific or mathematical wording. Do not issue this sheet with the student worksheet.
2.
State what is meant by superposition.
[1 mark]
- displacements add
3.
State what is meant by Young's double slits.
[1 mark]
- w = λD/s
4.
State what is meant by diffraction grating.
[1 mark]
- nλ = d sinθ
5.
State what is meant by stationary waves.
[1 mark]
- two opposite travelling waves of the same f
6.
State what is meant by the first harmonic.
[1 mark]
- λ/2 = L on a string
7.
State what is meant by refraction.
[1 mark]
- n = c/v = sin i / sin r
8.
State what is meant by optical fibre.
[1 mark]
- TIR along the core
9.
State what is meant by polarisation.
[1 mark]
- oscillations in one plane
10.
State what is meant by a photon in the photoelectric effect.
[1 mark]
- interacts with one electron
11.
Jac is asked about phase difference in a Eduqas Physics paper.
(a) [2 marks]
- in radians or degrees
(b) [3 marks]
- π rad is antiphase
12.
Jac is asked about superposition in a Eduqas Physics paper.
(a) [2 marks]
- constructive and destructive interference
(b) [3 marks]
- path difference nλ or (n+½)λ
13.
Jac is asked about Young's double slits in a Eduqas Physics paper.
(a) [2 marks]
- monochromatic coherent sources
(b) [3 marks]
- measures λ
14.
Jac is asked about diffraction grating in a Eduqas Physics paper.
(a) [2 marks]
- sharper maxima than two slits
(b) [3 marks]
- used to measure λ
15.
Jac is asked about stationary waves in a Eduqas Physics paper.
(a) [2 marks]
- nodes and antinodes
(b) [3 marks]
- harmonics on a string
16.
Jac is asked about the first harmonic in a Eduqas Physics paper.
(a) [2 marks]
- fundamental
(b) [3 marks]
- f = (1/2L)√(T/μ)
17.
w = λD/s. λ=6.0×10⁻⁷, D=1.5, s=0.50×10⁻³
[3 marks]
- Final answer: 1.8 mm
18.
nλ = d sinθ. n=1, d=2.0×10⁻⁶, θ=18°. λ
[3 marks]
- Final answer: 6.2 × 10⁻⁷ m
19.
First harmonic: L=0.80 m. λ
[3 marks]
- Final answer: 1.6 m
20.
n = 1.5, c=3.0×10⁸. v in glass
[3 marks]
- Final answer: 2.0 × 10⁸ m/s
21.
Critical angle if n=1.5 to air
[3 marks]
- Final answer: 41.8°
22.
Path difference for the 2nd bright fringe
[3 marks]
- Final answer: 2λ
23.
Jac carries out a Eduqas-style required practical linked to waves, superposition and optics. This is a typical Eduqas required-practical style question.
(a) [2 marks]
- Independent: the independent variable for this topic
- Dependent: the measured outcome
(b) [2 marks]
- keep all other variables constant
- so the test is fair / only one variable is changed
(c) [2 marks]
- repeat and calculate a mean / use a tighter method
24.
Jac carries out collecting valid data for waves, superposition and optics. This is a typical Eduqas required-practical style question.
(a) [2 marks]
- Independent: a chosen factor
- Dependent: a quantitative measurement
(b) [2 marks]
- calibrated instrument
- so the test is fair / only one variable is changed
(c) [2 marks]
- systematic error from zero error
25.
Jac carries out drawing a graph for waves, superposition and optics. This is a typical Eduqas required-practical style question.
(a) [2 marks]
- Independent: x-variable
- Dependent: y-variable
(b) [2 marks]
- same scale / same apparatus
- so the test is fair / only one variable is changed
(c) [2 marks]
- not drawing a line of best fit through the trend
26.
Jac carries out evaluating a method about waves, superposition and optics. This is a typical Eduqas required-practical style question.
(a) [2 marks]
- Independent: method change
- Dependent: precision / accuracy
(b) [2 marks]
- same sample size
- so the test is fair / only one variable is changed
(c) [2 marks]
- too few repeats
27.
Compare phase difference with superposition.
[4 marks]
- how far out of step two waves are
- displacements add
- give one linked difference
28.
Compare superposition with Young's double slits.
[4 marks]
- displacements add
- w = λD/s
- give one linked difference
29.
Compare Young's double slits with diffraction grating.
[4 marks]
- w = λD/s
- nλ = d sinθ
- give one linked difference
30.
Compare diffraction grating with stationary waves.
[4 marks]
- nλ = d sinθ
- two opposite travelling waves of the same f
- give one linked difference
31.
Apply your knowledge of refraction to this situation: towards the normal if slower
[3 marks]
- towards the normal if slower
32.
Apply your knowledge of optical fibre to this situation: cladding of lower n
[3 marks]
- cladding of lower n