Question

Consider the following statements: 

1. If a person looks at a coin which is in a bucket of water, the coin will appear to be closer than it really is. 

2. If a person under water looks at a coin above the water surface, the coin will appear to be at a higher level than it really is.

Which of the above statements is/are correct?

(a) 1 and 2 (b) 1 alone (c) 2 alone (d) neither 1 nor 2

Answer 1

(a) Refraction is the change in direction of a wave due to a change in its speed. This is most commonly observed when a wave passes from one medium to another at any angle other than 90° or 0°. Refraction of light is the most commonly observed phenomenon. In both cases the phenomenon of refraction is applicable because there will be a change in the direction and speed as light enters from one media to other. In case 1 light for observer outside water the light ray is travelling from denser medium (water) to rarer medium (air). Thus, image of coin will appear closer due to refraction. Whereas in case 2 for observer under water refraction also takes place but in opposite way as light travels from rarer medium (air) to denser medium (water) .Thus, the image of coin will appear at a higher level than actual position of coin.