The minimum distance (approximately) between a source and obstacle for the echo to be heard is:

• 10 m

• 24 m

• 17 m

• 34 m

Bats detect obstacles in their path by receiving the reflected:

• radio waves

• electromagnetic waves

• ultrasonic waves

• infrasonic waves

The method of detecting location, presence and direction of movement of distant objects by reflecting a beam of sound waves is called:

• RADAR

• SONAR

• MIR

• CRO

The technique employed by bats to locate prey or to navigate is called:

• SONAR

• RADAR

• echolocation

• telescopy

Mechanical waves can be:

• transverse

• longitudinal

• light waves

• both (a) and (b)

The time period of a sound source is the inverse of its:

• amplitude

• wavelength

• velocity

• frequency

A high amplitude sound will carry farther because it has higher:

• frequency

• energy

• velocity

• pitch

The distance between a crest and its adjacent trough of a sound wave is x cm. The wavelength of this sound wave is:

• x/2 cm

• x cm

• 2 x cm

• 3/2 x cm

The speed of sound in a medium depends upon:

• amplitude

• frequency

• wavelength

• properties of medium

Which of the following will remain unchanged when a sound wave travels in air or in water?

• amplitude

• wavelength

• frequency

• velocity