2.2% of the light emitted by asource of luminous intensity 500 condela falls normally on a circular surface of radius 10cm. Calculate the average illumination of the surface.

A beam of light having wavelength lambda and intensity 1 falls normally on an area A of a clean surface then find out the number of photon incident on the surface.

Calculate the illuminance at a surface distance 0.5m from a ligth source of luminous intensity 200 cd, assuming normal incidence. If the area of the surface be 0.25m^(2) , what is the luminous flux on this area ?

Violet light (lambda=4000A ) of intensity 4watt/m^(2) falls normally on a surface of area 10cm xx 20cm .Find (i) the energy received by the surface per second.(ii) the number of photons hitting the surface the surface per second,(iii) If surface is titled such that plane of the surface makes an angle 30^(@) with light beam, find the number of photons hitting the surface per second.

Calculate the moment of inertia of uniform circular disc of mass 500 g, radius 10 cm about : diameter of the disc

A small LED, emitting light is placed at x distance above a spherical glass of refractive index 1.5 and radius of curvature 30 cm. The image of the LED is formed at a distance of 150 cm away from the surface of sphere along the direction of incident light. Calculate the distance between LED light and the surface of spherical glass.

The light from th esun is found to have a maximum intensity near the wavelength of 470nm. Assuming that the surface o f the sun emits as a blackbody, calculate the temperture of the surface of the sun.

If an electron is moving around a nucleus of charge 3theta in a circular orbit of radius 10^(-10) m,then calculate the initial frequency of light emitted by the electron.

Iluminance of 2.4 xx 10^(5)lm//m^(2) of the surface is produced by sunlight falling normally on the surface of the earth. The distance of the earth the sun is 1.5 xx 10^(8)km . Calculate the luminous intensity and luminous flux of the sun.