Question

Ans.(a) 3 x 108 ms
ricals :
1. The heart of a man beats 75 times a minute. What
is its (a) frequency and (b) time period ?
its frequency
Ans. (a) 1.25 s-1, (b) 0.8 s
2. The time period of a simple pendulum is 2 s. Find
Ans. 0.5 Hz
3. The separation between two consecutive crests
in a transverse wave is 100 m. If wave velocity is
20 m s-1, find the frequency of wave.
Ans. 0:2 Hz
4. A longitudinal wave travels at a speed of 0.3 ms and
the frequency of wave is 20 Hz. Find the separation
between the two consecutive compressions.
Ans, 1.5 x 10-2 m (or 1.5 cm)
5. A source of wave produces 40 crests and 40 troughs
in 0.4 s. What is the frequency of the wave ?
Ans. 100 Hz
6. An observer A fires a gun and another observer B at
a distance 1650 m away from A hears its sound. If
the speed of sound is 330 m s-, find the time when
B will hear the sound after firing by A. Ans, 5 s
7. The time interval between a lightning flash and the
first sound of thunder is 5 s. If the speed of sound
in air is 330 m s-1, find the distance of flash from
the observer.
Ans. 1650 m
8. A boy fires a gun and another boy at a distance hears
the sound of fire 2.5 s after seeing the flash. If speed
of sound in air is 340 m s-1, find the distance
Ans. 850 m
between the boys.
9. An observer sitting in line of two tanks, watches the
flashes of two tanks firing at each other at the same time,
but he hears the sounds of two shots 2 s and 3.5 s after
seeing the flashes. If distance between the two tanks is
10 m, find the speed of sound. Ans. 340 m s-1
nd take to travel in (a) an iron
th? Take speed​

Answer 1

Answer:

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