OCR Gateway Science Physics A (J249)
GCSE Physics
Answer sheet
P4 Waves and radioactivity
Separate mark scheme — do not issue with the student worksheet
Time guide: — · Questions: 32 · Total marks: 104
Written in OCR Gateway A style. Use the equation sheet. Give answers to 2 or 3 significant figures where appropriate.
Indicative marking points. Award marks for equivalent scientific or mathematical wording. Do not issue this sheet with the student worksheet.
1.
State what is meant by a transverse wave.
[1 mark]
oscillations perpendicular to direction of energy transfer
2.
State what is meant by a longitudinal wave.
[1 mark]
oscillations parallel to energy transfer
3.
State what is meant by amplitude.
[1 mark]
maximum displacement from equilibrium
4.
State what is meant by wavelength.
[1 mark]
distance between two corresponding points
5.
State what is meant by frequency.
[1 mark]
waves per second
6.
State what is meant by wave speed.
[1 mark]
v = fλ
7.
State what is meant by the EM spectrum.
[1 mark]
radio → microwave → IR → visible → UV → X-ray → gamma
8.
State what is meant by reflection.
[1 mark]
wave bounces off a boundary
9.
State what is meant by refraction.
[1 mark]
wave changes speed and direction in a new medium
10.
State what is meant by ultrasound.
[1 mark]
sound above 20 kHz
11.
Grace is asked about a transverse wave in a OCR Physics paper.
(a) [2 marks]
light, water, S-waves
(b) [3 marks]
has peaks and troughs
12.
Grace is asked about a longitudinal wave in a OCR Physics paper.
(a) [2 marks]
sound, P-waves
(b) [3 marks]
compressions and rarefactions
13.
Grace is asked about amplitude in a OCR Physics paper.
(a) [2 marks]
related to loudness / brightness
(b) [3 marks]
not the length of the wave
14.
Grace is asked about wavelength in a OCR Physics paper.
(a) [2 marks]
e.g. peak to peak
(b) [3 marks]
metres
15.
Grace is asked about frequency in a OCR Physics paper.
(a) [2 marks]
hertz
(b) [3 marks]
pitch of sound
16.
Grace is asked about wave speed in a OCR Physics paper.
(a) [2 marks]
also distance/time
(b) [3 marks]
same in a given medium for that wave type
17.
v = fλ. 200 Hz, 1.7 m
[3 marks]
Final answer: 340 m/s
18.
λ if v=3×10⁸ and f=6×10¹⁴
[3 marks]
Final answer: 5 × 10⁻⁷ m
19.
T = 1/f. f = 50 Hz
[3 marks]
Final answer: 0.02 s
20.
A wave travels 60 m in 0.20 s. Speed
[3 marks]
Final answer: 300 m/s
21.
How many waves in 4.0 s if f=25 Hz
[3 marks]
Final answer: 100
22.
A ripple has λ=4 cm and f=5 Hz. Speed in m/s
[3 marks]
Final answer: 0.20 m/s
23.
Grace carries out a OCR-style required practical linked to waves. This is a typical OCR 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.
Grace carries out collecting valid data for waves. This is a typical OCR 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.
Grace carries out drawing a graph for waves. This is a typical OCR 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.
Grace carries out evaluating a method about waves. This is a typical OCR 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 a transverse wave with a longitudinal wave.
[4 marks]
oscillations perpendicular to direction of energy transfer
oscillations parallel to energy transfer
give one linked difference
28.
Compare a longitudinal wave with amplitude.
[4 marks]
oscillations parallel to energy transfer
maximum displacement from equilibrium
give one linked difference
29.
Compare amplitude with wavelength.
[4 marks]
maximum displacement from equilibrium
distance between two corresponding points
give one linked difference
30.
Compare wavelength with frequency.
[4 marks]
distance between two corresponding points
waves per second
give one linked difference
31.
Apply your knowledge of the EM spectrum to this situation: all travel at c in vacuum
[3 marks]
all travel at c in vacuum
32.
Apply your knowledge of reflection to this situation: angle i = angle r