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.

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

Two poles of heights 6m and 11 m stand on plane ground. If the distance between their feet is 12 m, find the distance between their tops.

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

A lamp of luminous intensity 100 cd is held at a distance of 2 m from a vertical wall. A plane mirror is fixexd on the opposite wall which is at a distance of 4 m from the lamp. Calculate the illumainance on the wall opposite to the mirror at a point on the horizontal line through the lamp. Also calculate the luminous flux on a small area or 0.02 m^(2) surrounding the point.

Two poles of heights 6m and 11m stand on a plane ground.If the distance between their feet is 12m. Find the distance between their tops.