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Question 1             (1+4=5 marks)

a) The intensity of a wave is:

A) proportional to both the amplitude squared and the frequency squared.

B) proportional to the amplitude squared and inversely proportional to the frequency squared.

C) inversely proportional to the amplitude squared and proportional to the frequency squared.

Answer: A

b) The graph below is a snapshot of t =0 s of a 10.0 Hz wave travelling to the right.

i. Find the amplitude of the wave.

ii. What is the wavelength of this wave?

iii. Calculate the period of the wave.

iv. What is the wave speed?

Question 2                 (1+2=3 marks)

A uniform narrow tube, 2.0m long, is open at both ends. It resonates at two successive harmonics of frequencies 255 Hz and 340 Hz.

a) Find the fundamental frequency.

b) Calculate the speed of sound of the gas in the tube.

Question 3                 (1+2=3 marks)

A particular string resonates in four loops at a frequency of 280 Hz.

a) Find the first harmonic frequency.

b) Calculate the second and third harmonic.

Question 4                 (2+2+2=6 marks)

A source of sound has an intensity level of 120 dB at a distance of 350 m.

a) What is the intensity of the 120dB?

b) Calculate the intensity of 120dB at a distance of 6 km.

c) Find the sound intensity level at a distance of 6 km.

Question 5                    (1+1+1=3 marks)

A glass container is filled with a liquid. A beam of light from outside the container strikes the glass at a 55.5° angle to the perpendicular as shown in the figure below.

a) Calculate the angle of this ray when enters the glass (angle of refraction).

b) Find the angle of this ray when enters the liquid.

c) Find the speed of light in the liquid.