A student does the experiment on tracing the path of a ray of light passing through a rectangular glass slab for different angles of incidence. He can get a correct measure of the angle of incidence and the angle of emergence by following the labelling indicated in figure:

In optics an object which has higher refractive index is called

The number of images observable between two parallel mirrors is :

Total internal reflection of light is possible when light enters from :

A man runs towards the plane mirror at 2 m/s. The relative speed of his image with respect to him will be:

Refractive index:

Value of tan30°/cot60° is:

If cos A = 4/5, then tan A = ?

value of the expression

[cosec (75° + θ) – sec (15° - θ) – tan (55° + θ) + cot (35° - θ)] is

sin A = 1/2 and cos B = 1/2,

then A + B = ?

If cos (A + B) = 0, then sin (A – B) is reduced to:

cos 0°. cos 1°. cos 2°. cos 3°… cos 89° cos 90° is

If x and y are complementary angles, then

If A and (2A – 45°) are acute angles such that sin A = cos (2A – 45°), then tan A is equal to

If sin θ + sin² θ = 1, then

cos² θ + cos4 θ = .....

What is the minimum value of sin A,

0 ≤ A ≤ 90°

If in ΔABC, ∠C = 90°,

then sin (A + B) =