A ray of light travelling in the directi...

A ray of light travelling in the direction `(1)/(2)``(hati,+sqrt3hatj)` is incident on a plane mirror. After reflection, it travels along the direction `(1)/(2)(hati-sqrt3hatj)` . The angle of incidence is

`30^(@)`

`45^(@)`

`60^(@)`

`75^(@)`

Text Solution

Verified by Experts

The correct Answer is:

Let `theta` be angle between the given rays,
`:. cos theta = (((hati+sqrt(3)hatj)/(2)).((hati-sqrt(3)hatj)/(2)))/(|(hati+sqrt(3)hatj)/(2)||(hati-sqrt(3)j)/(2)|) = ((1.3)/(4))/(1) = -1/2`
`theta = cos^(-1)(-1/2) = 120^(@)`
Angle of incidence, `i = (180^(@) - theta)/(2)= (180^(@) - 120^(@))/(2) = 30^(@)`

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A ray of light travelling in the direction 1/2 (hati+sqrt(3)hatj) is incident on a plane mirror. After reflectiion, it travels along the direction 1/2(hati+sqrt(3)hatj) . The angle of incidence is

`30^(@)`

`45^(@)`

`60^(@)`

`75^(@)`

A light ray is incident normally on a plane mirror. The angle of reflection will be

`120^@`

`90^@`

`45^@`

`0^@`

A light ray is incident along the principal axis of a mirror after reflection ______.

retraces its path

passes through center of curvature

makes zero angle with the normal.

All the above.