A man is standing at a distance of 12 m from a cliff. Will he be able to hear a clear echo of his sound? Give a reason for your answer.

A man standing 25 m away from a wall produces a sound and receives the reflected sound. Will the man be able to hear a distinct echo ? Give a reason for your answer.

Can two persons hear each other on moon's surface ? Give reason to support your answer.

How would the sky appear when seen from the space (or moon)? Give reason for your answer.

An observer stands at a distance of 660 m from a cliff and fires a gun. After what time period will he hear the echo, if the sound travels at a speed of 330 m/s?

A man standing at some distance from a cliff hears the echo of sound after 2s. He walks 495 m away from the cliff. He produces a sound there and receives the echo after 5s. What is the speed of sound?

An observer stands at a certain distance away from a cliff and produces a loud sound. He hears the echo of the sound after 1.8 s. Calculate the distance between the cliff and the observer if the velocity of sound in air is 340ms^(-1) .

Ranbir claims to have obtained an image twice the size of the object with a concave lens. Is he correct? Give a reason for your answer.

A girl is sitting in the middle of a park of dimension 12 m xx 12 m . On the left side of it there is a building adjoining the park and on right side of the park, there is a road adjoining the park. A sound is produced on the road by a cracker. Is it possible for the girl to hear the echo of this sound ? Explain your answer.

In which medium the speed of sound is more : humid air or dry air ? Give a reason to your answer.