A small lamp having the form of a unfromly luminous sphere of radius `R = 6/0 cm` is suspended at a height `h = 3.0 m` above the floor. The luminance o fthe lamp is equal to `L = 2.0. 10^(4) cd//m^(2)` and is independent of direction. Find the illuminance of the floor directly below the lamp.

A small lamp having the from of a unifromly sphere of radius R=6 cm is suspended at a height h=3m above the floor. The luminance of the lampis equal to L=2xx10^(4) cd//m^(2) . Find the illuminance of the floor below the lamp. (Hint: P=sumLDeltaScostheta=LxxpiR^(2))

A man of 50 kg mass is standing in a gravity free space at a height of 10m above the floor. He throws a stone of 0.5 kg mass downwards with a speed 2m//s . When the stone reaches the floor, the distance of the man above the floor will be

A man of 50 kg mass is standing in a gravity free space at a height of 10m above the floor. He throws a stone of 0.5 kg mass downwards with a speed 2m//s . When the stone reaches the floor, the distance of the man above the floor will be

A man of 50 kg mass is standing in a gravity free space at a height of 10 .m above the floor.-He throws a stone of 0.5 kg.mass downwards with a speed 2 m//s . When the.stone reaches the floor,the distance of the man above the floor will be

A man of 50 kg mass is standing in a gravity free space at a height of 10m above the floor. He throws a stone of 0.5 kg mass downwards with a speed 2m//s . When the stone reaches the floor, the distance of the man above the floor will be

street lamps of 10 cm diameter and 1.8xx10^(5)cdm^(2) luminance are suspended at a height of 12 m the distance bewteen them being 40 m Find the illuminance under each lamp and mid-way between them.

A point source is suspended at a hight h = 1.0 m over the centre of a round table of radius R = 1.0 m . The luminous intensity I of the source depends on direction so that illuminance at all points of the table is the same. Find the function I (theta) , where theta is the angle between the radiation direction and the vertical, as well as the luminous flux reaching the table if I (0) = I_(0) = 100 cd .

An illuminant shaped as a plane horizontal disc S = 100 cm^(2) in area is suspended over the centre of a round table of radius R = 1.0 m . Its luminance does not depend on direction and is equal illuminant be suspended to provide maximum illuminance at the circumference of the table ? How great will that illuminance be? The liuminant is assumed to be a point source.

If anelectric lamp be suspended at a height h from a circular table of radius r, prove that the intensity of illumination at thecentre of the table is (1+(r^(2))/(h^(2)))^(3//2) times that at the edge of the table.