Question

It was a rainy day in Bangalore. Rohit was sitting besides the window when he saw a lightning. He started his stop watch. He found that after 22 seconds of lightning its roaring was heard. Calculate the height of the clouds which caused this lightning. Given, speed of light = 3×108 ms−1 and speed of sound = 340 ms−1.

A
10 km
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
8.5 km
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
7.5 km
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D
5 km
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is C 7.5 kmSpeed of light is too high. So you can assume there is no time delay in colliding clouds and lightning. Since the time taken for light to travel from clouds to earth is approximately 0, we can say that lightning happened at t=0 and sound reached our ears at 22 s. Given, speed of sound =340 ms−1 We know, distance=speed×time ∴Height of clouds=22×340=7480 m≈7.5 km.

Suggest Corrections
0
Related Videos
Time, Average Speed and Velocity
MATHEMATICS
Watch in App
Explore more