Two lamp posts are 12 m apart and are fitted with 1000 cd lamp each at a height of 5m above the ground. Calculate the illumination on the ground (i) under each lamp and (ii) midway between the two lamps.

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 lamp of 120 candela hangs at a height of 4 m excathy above the centre of a circular table of diameter of 6.m Caluclate the illuminance at the centre and at the edge of the table.

A 1.5m tall boy stands at a distance of 3m from a lamp post and casts a shadow of 4.5m on the ground. Find the height of the lamp.

An infinite number of lamps, each of luminous intensity 100 cd are placed 1 m apart in a horizontal line perpendicular to a wall. The nearest being 1 m from the wall. Calculate the illuminance at a point on the wall lying on the line through the lamps. Given sum_(1) =1//n^(2)=pi^(2)//6

A lamp is hanging at a height of 4 m above a table. The lamp is lowered by 1 m . The percentage increase in illuminace will be

On a very hot day, a boy standing at a large distance observers a neon monochromatic lamp hanging at a height h above the ground. He observe the lamp as shown in the figure

If a 1.5 m-tall girl stands at a distance of 3 m from a lamp-post and casts a shadow of length 4.5 m on the ground, then the height of the lamp-post is

A 60W lamp is rated at 0.8 watt/candela. Calculate (i) luminous intensity of the lamp, (ii) luminous flux of the lamp, and (iii) illuminance at a distance of 2m from the lamp.