Choose The Only Wrong Statement From The Following.

When a ray of light is incident on a glass slab at an angle of 60^o, the angle between the reflected and refracted rays is 90^o. The refractive index of glass is  

The polarising angle for glass is 

What is the SI unit of luminous intensity?

What are the dimensions of luminous intensity?   

What is the luminous intensity of a lamp which produces an illuminance of 12 lux at a distance of 5.0 m from it?  

To print a photograph from a negative, the time of exposure to light from a lamp placed 60  cm away is 2.5 s. What exposure time is required if the lamp is placed 1.2 m away?

A lamp placed at a distance of 50.0 cm from a screen on one side produces the same illumination as a standard 60 cd candle placed 100 cm away on the other side of the screen. What is the luminous intensity of the lamp?

An observer moves towards a stationary plane mirror at a speed of 4 ms^–1. With what speed will his image move towards him?  

Which mirror should be used to obtain a parallel beam of light from a small lamp?

A short linear object of length L lies on the axis of a spherical mirror of focal length f at a distance u from the mirror. Its image has an axial lengthL’ equal to