Home
Class 12
PHYSICS
A lamp rated at 100 cd hangs over the mi...

A lamp rated at 100 cd hangs over the middle of a round table with diameter 3 m at a height of 2 m . It is replaced by a lamp of 25 cd and the distance to the table is changed so that the illumination at the centre of the table remains as before. The illumination at edge of the table becomes X times the original. Then X is

Promotional Banner

Similar Questions

Explore conceptually related problems

A lamp is hanging along the axis of a circular table of radius r. at what height should the lamp be placed above the table so that the intensity of illumination at the edge of the table is (1)/(8) of that at its centre ?

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.

An electric bulb is hanging above the centre of a circular table of radiys 3m at a height of 3m from the its centre. Find the ratio of illuminance at the centre and at a point on the edge of the table.

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.

At what height should a lamp be hung above the centre of a round table of radius R to otain the maximum illumination at its edges?

An electric lamp hangs 3 m above one end of a table, which is 4 m long. Compare the intensity of illumination at the two ends of the table.