12

MAXIMUM TIME: 35 minutes

MAXIMUM MARKS: 20 marks

1.   What is wavelength? (1)

2.   What is pitch? (1)

3.   What should be the time interval between the originated sound and the reflected sound to heard distinctly? (1)

4.   A ship sends out ultrasound that returns from the seabed and is detected after 3.42 s. If the speed of ultrasound through seawater is 1531 m/s . What is the distance of the seabed from the ship? (3)

5.   Define amplitude, time period and frequency of sound water. (3)

6.   Why do we say that sound waves are longitudinal? (2)

7.   Give three uses of ultrasound. (3)

8.   Sound cannot travel in vacuum. Describe an experiment to demonstrate this. (4)

9.   A child watching Dussehra from a distance sees the effigy of ravana burst into flames and hears the explosion associated with it 2 sec after that. How far was he from the effigy if the speed of sound in air that night was 335m/sec ? (2)