IB Waves AHL

page 1


SHM, The Doppler Effect, Interference, Single Slit Diffraction, Resolution




A 4kg mass oscillates on a spring as shown, performing simple harmonic motion (SHM). The amplitude of oscillation is 10cm, and the angular velocity is 5 rad s-1 .


Oleg Alexandrov http://commons.wikimedia.org/

1. The potential energy due to SHM at the centre of oscillation is

  • A. 0 J
  • B. 0.5 J
  • C. 1 J
  • D. 5 KJ

2. The total energy of the system is

  • A. 5 J
  • B. 0.5 J
  • C. 1 J
  • D. 5 KJ

3. The maximum velocity is

  • A. 0.5 ms-1
  • B. 5 ms-1
  • C. 50 ms-1
  • D. 500 ms-1

4. The time period of the spring shown above is measured to be T.

If the spring is replaced with one where the spring constant k is 4 times larger, and the mass is reduced to 1kg, the new time period will be

  • A. 4T
  • B. 2T
  • C. T/2
  • D. T/4

5. A pendulum in a clock performs SHM as it oscillates with amplitude 0.2m. The time taken for an oscillation is exactly 2s. The value of ω (angular velocity) and f (frequency) are therefore

  ω (rad s-1) f (Hz)
A π 0.5
B π π
C 4 π 0.5
D 4 π π

6. A police car is moving towards an observer with its siren switched on. Compared to the source, the sound as measured by the observer will have

  • A. a higher frequency and higher velocity
  • B. a lower frequency and a higher velocity
  • C. a higher frequency and the same velocity
  • D. a lower frequency and the same velocity

7. A galaxy is moving away from Earth at 1% the speed of light. Radio waves of original frequency 106 Hz will be observed to have a frequency of

  • A. 1.1 x 106 Hz
  • B. 1.01 x 106 Hz
  • C. 9.9 x 105 Hz
  • D. 9.99 x 105 Hz

8. The Doppler effect can be used to find the velocity of a source. Whcih of the following statements gives the application AND correctly states the wave that can be used ?

I Speed cameras on roads, using radio waves
II Blood flow rates, using ultrasound
III Speed of galaxy recession, using visible light
  • A) I only
  • B) I and II only
  • C) II and III only
  • D) All 3 statements