A small source of light is to be suspended directly above the centre of a circular table of radius R . What should be the height of the light source above the table so that the intensity of light is maximum at the edges of the table compared to any other height of the source

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 ?

An isotropoic point source of light is suspeneded h metre vericlaly above the centre of circular table of radius r metre.Then the ratio of illumenances at the centre to that at the edge of the table is

An isotropoic point source of light is suspeneded h metre vericlaly above the centre of circular table of radius r metre.Then the ratio of illumenances at the centre to that at the edge of the table is

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 student is studying a book placed near the edge of a circular table of radius R. A point source of light is suspended directly above the centre of the table. What should be the height of the source above the table so as to produce maximum illuminance at the position of the book ?

A student is studying a book placed near the edge of a circular table of radius R. A point source of light is suspended directly above the centre of the table. What should be the height of the source above the table so as to produce maximum illuminance at the position of the book ?

A student is studying a book placed near the edge of a circular table of radius R. A point source of light is suspended directly above the centre of the table. What should be the height of the source above the table so as to produce maximum illuminance at the position of the book ?