Which mirror should be used to obtain a parallel beam of light from a small lamp?
Concave mirror should be used to obtain a parallel beam of light from a small lamp.
A parallel beam of white light is reflected from a thin wedge-shaped film. The colour of the fringe at the edge of the wedge will be
When a ray of light is incident on a glass slab at an angle of 60o, the angle between the reflected and refracted rays is 90o. 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?
Choose the only wrong statement from the following.