Physics - Study Mode

[#606] Bats can sense obstacles because they produce
Correct Answer

(B) Ultrasonic sound waves

Explanation

Solution: Bats are capable of avoiding obstacles that they encounter, even in complete darkness. This is because they emit ultrasound (high frequency sound) and analyse the echo produced when the sound hits objects on their path. Prey capture without the aid of echolocation by some bats is also described.

[#607] Which term is not associated with sound wave?
Correct Answer

(C) Candela

Explanation

Solution: Candela is the SI unit of luminous intensity.

[#608] Velocity of sound in air does not depend on
Correct Answer

(C) Pressure of air

Explanation

Solution: Assuming air to be an ideal gas, the speed of sound depends on temperature only. As air temperature increases, so does the speed of sound and vice versa. The speed of sound is completely independent of air pressure because the air pressure and air density are proportional to each other at the same temperature.

[#609] Speed of sound in air is unaffected by change in
Correct Answer

(A) Pressure

Explanation

Solution: Humidity has little effect on the speed of sound, nor does air pressure by itself. Air pressure has no effect at all in an ideal gas approximation. This is because pressure and density both contribute to sound velocity equally, and in an ideal gas the two effects cancel out, leaving only the effect of temperature.

[#610] RADAR is used for
Correct Answer

(A) Detecting and locating the position of objects such as Aeroplanes

Explanation

Solution: Radar, electromagnetic sensor used for detecting, locating, tracking, and recognizing objects of various kinds at considerable distances. It operates by transmitting electromagnetic energy toward objects, commonly referred to as targets, and observing the echoes returned from them.