`hatn_(1)` is the unit vector along incident ray, `hatn_(2)` along normal and `hatn_(3)` is the unit vector along reflected ray, then which of the following must be true?

The unit vector along hati+hatj is

The unit vector along hati+hatj is

The unit vector along hati+hatj is :

The unit vector along hati+hatj is :

The unit vector along 2hati+3hatj is

If hatn is a unit vector along the direction of vecA then hatn is

A ray of light is reflected by a plane mirror. hatepsilon_(0), hate and hatn be the unit vectors along the incident ray, reflected ray and the normal to the reflecting surface respectively. Which of the following gives an expression for hate ?

If hatn is the unit vector in the direction of vecA then hatn is equal to

If hat(i) denotes a unit vector along incident light ray, hat( r) a unit vector along refracted ray into a medium of refractive index mu and hat(n) unit vector normal to boundary of medium directed towards incident medium, then law of refraction is