Read the statements and answer the questions that follow.
(i) Explain why the speed of sound in water is greater than that in air, even when both are at the same temperature.
(ii) State two reasons why sonar equipment uses ultrasonic frequencies instead of audible sound.
(iii) A student claims that the formula d=2vt, commonly used for measuring distance by echo in air, is not applicable in water. Do you agree with this claim? Give reasons for your answer.