the velocity of sound in air is 340 ms^-1, a person singing a note of frequency 250 cps is producing sound waves with a wavelength of ________

(a)

0.7

(b)

1.36 cm

(c)

1.36 m

(d)

85 km

As a transverse wave strikes against a fixed end ________.

(a)

its phase changes by 180°, but velocity does not change

(b)

its phase does not change, but velocity changes

(c)

its velocity changes and phase too changes by 180°

(d)

nothing can be predicted about changes in its velocity and phase

A source of sounds is travelling with a velocity of 40 km/hr towards an observer and emits sound of frequency 2000 Hz. If the velocity of sound is 1220 km/hr, then what is the apparent frequency heard by the observer?

(a)

2068 Hz

(b)

2180 Hz

(c)

2000 Hz

(d)

1980 Hz

A vehicle with a horn of frequency n is moving with a velocity of 30 m/s in a direction perpendicular to the straight line joining the observer and the vehicle. The observer perceives the sound to have a frequency n + n₁. Then (if the sound velocity in air is 300 m/s) _________

(a)

n₁ = 10 n

(b)

n₁ = 0

(c)

n₁ = -0.1 n

(d)

n₁ = 0.1 n

The Doppler effect is applicable for ________.

(a)

light waves

(b)

sound waves

(c)

space waves 

(d)

both (a) and (b)