A wave travelling from water to glass suffers a change in its speed at the common boundary. Which of the following properties explains this observation?
A man 1.8m tall stands 3m away from a pin hole camera. If the distance between the pin hole and the screen of the camera is 0.3m. Calculate the height of the image of the man produced by the camera
During a thunderstorm, lightning and thunder occurred simultaneously in the atmosphere. An observer on the earth surface's sees the lightning flash shortly before hearing the thunder. This is because the
A.
atmospheric pressure is higher at the surface than at the higher altitudes
B.
speed of sound is less than that of light
C.
temperature of the atmosphere decreases with altitude
