A lens if placed between a source of light and a wall. It forms images of area` A_(1)` and `A_(2)` on the wall for its two different positions. The area of the source or light is

A lens is placed between a source of light and a wall. It forms images of are A_(1) and A_(2) on the wall, for its two different positions, the area of the source of light is

A lens is placed between a souce of light and a wall.It forms images of areas A_1 and A_2 on the wall for its two different positions.The area of the source of light is

A lens is placed between the source of light and a wall. It forms images of area A_(1) and A_(2) on the wall for its two displaced positions. The area of source of light is

A lens is placed between a source of light and screen. It forms real image on screen for two different positions. If height of one image is 20 cm and the other is 80 cm, then the height of source of light (in cm) is_____.

What is the difference between coherent and incoherent sources of light?

List out the difference between a point source and an extended source of light.

A source of light is located at a disatnce l = 90 cm from a screen. A thin converging lens provides the sharp image of the source when placed between the source of light and the screen at two positions. Determine the focal length o fthe lens if (a) the distance between the two positions of the lens is Delta l = 30 cm , (b) the transverse diamensions of the image at one position o fthe lens are eta = 4.0 greater than those at the pther position.