A point light source illuminates a screen the, maximum illuminance being `I_(0)` How will the illuminance of this point change if a large plane mirror or 100% reflectance is placed behind the source at half the distance between the source and the screen?

A point source of light is placed in front of a plane mirror.

A point source of light is placed in front of a plane mirror.

A point source of light is placed in front of a plane mirror.

A point source of light 'S' at a distance d from the screen A produces light intensity I_(0) at the centre of the screen. If a completely reflecting mirror M is placed at a distance d behind the source as shown in the figure, find the intensity at the centre of the screen

A screen is placed at a distance of 5 cm from a point source. A 5 mm thick piece of glass of refractive index 1.5 is placed between them. What is the length of optical path between the source and the screen ?

A point source kept at a distance of 1000 m has a illumination I. To change the illumination to 16I, the new distance should become

A point source is kept at a distance of 1000 m has an illumination I. To change the illumination to 16I the new distance should become