1) Four sound waves are imaged on a c.r.o. using the same gain and timebase values.

Which sound wave has the highest frequency?

2) A man standing at P in the middle of a rectangular-shaped room claps his hands once.

A microphone placed right next to him detects two distinct echoes.

Taking the speed of sound in air to be 340 m s^-1, what is the time interval between the two echoes?

3) The depth of the seabed from position P to position Q is shown below.

Ultrasonic pulses are sent from a ship to the seabed as it travels from P to Q.

Which of the following graphs correctly represents the variation of the time interval between the emitted pulse and its echo from the seabed received by the ship as it moves from P to Q?

4) The following diagram shows the displacement-distance graph for a wave.

What is the amplitude of the wave?

5) A microphone connected to an oscilloscope receives the note emitted by a tuning fork and gives a pattern on the oscilloscope as shown in the figure below.

The four patterns below are produced by four musical instruments. Which of them has the same pitch as the tuning fork?