6.2 Wave properties and the wave equation
9 exam questions worth 22 marks. Write your answer, open the mark scheme, then give yourself the marks you earned. Your answers are saved on this device.
0 / 22
What is the unit of frequency?
Choose one answer.
Correct Not quite: the answer is Hertz
Mark scheme
B: Hertz
Model answer
Hertz (B).
A wave has a frequency of 20 Hz and a wavelength of 0.50 m. Calculate the speed of the wave.
Mark scheme
v = f λ = 20 × 0.50 (1); 10 m/s (1)
Model answer
v = f λ = 20 × 0.50 = 10 m/s.
A water wave travels at 0.60 m/s with a wavelength of 0.020 m. Calculate its frequency.
Mark scheme
f = v ÷ λ (1); 0.60 ÷ 0.020 (1); 30 Hz (1)
Model answer
f = v / λ = 0.60 / 0.020 = 30 Hz.
The speed of sound in air is 330 m/s. Calculate the wavelength of a sound wave of frequency 1.5 kHz.
Mark scheme
f = 1500 Hz (1); λ = v ÷ f = 330 ÷ 1500 (1); 0.22 m (1)
Model answer
f = 1500 Hz. λ = v / f = 330 / 1500 = 0.22 m.
A wave has a period of 0.040 s. Calculate its frequency.
Mark scheme
f = 1 ÷ T = 1 ÷ 0.040 (1); 25 Hz (1)
Model answer
f = 1 / T = 1 / 0.040 = 25 Hz.
An electromagnetic wave has a frequency of 6.0 × 10¹⁴ Hz and travels at 3.0 × 10⁸ m/s. Calculate its wavelength.
Mark scheme
λ = v ÷ f (1); 3.0 × 10⁸ ÷ 6.0 × 10¹⁴ (1); 5.0 × 10⁻⁷ m (1)
Model answer
λ = v / f = 3.0 × 10⁸ / 6.0 × 10¹⁴ = 5.0 × 10⁻⁷ m.
A student sees 12 waves pass a point on a pond in 6.0 s. The wavelength is 0.15 m. Calculate the speed of the waves.
Mark scheme
f = 12 ÷ 6.0 = 2.0 Hz (1); v = f λ (1); 2.0 × 0.15 (1); 0.30 m/s (1)
Model answer
f = 12 / 6.0 = 2.0 Hz. v = f λ = 2.0 × 0.15 = 0.30 m/s.
State what the amplitude of a wave tells you about the wave, and give the effect of increasing the amplitude of a sound wave.
Mark scheme
the amplitude shows the energy carried by the wave / maximum displacement (1); a louder sound (1)
Model answer
A larger amplitude means the wave transfers more energy. For sound, it makes the sound louder.
A wave travels from air into water. State which property of the wave stays the same and explain why.
Mark scheme
the frequency (1); because frequency is determined by the source (1)
Model answer
The frequency stays the same, because it is determined by the source of the wave.
Found a mistake?