Question

16) The depth of pond is ....... if it seems to be 10m a) 10m b) 7.7m c) 13.3m d) 20m​

Answer 1

The answer is d) 20 m.

The depth of pond is 20 m if it seems to be 10 m.

The formula relating real depth and app. depth :

$\boxed {A = \frac{R}{n}}}$

In this case, refractive index has to be an whole number for real depth to give a whole number for app. depth.

• Then, real depth must be a multiple of 10, but refractive index cannot be 1
• The option is 20 m