A laser beam of pluse power `10^(12)` watt is focussed on an object are `10^(-4) cm^(2)`. The energy flux in `watt//cm^(2)` at the point of focus is

A black body emits 10 watts per cm^(2) at 327^(@)C . The sun radiates 10^(5) watt per cm^(2) . Then what is the temperature of the sun ?

A beam of unpolarised light having flux 10^(-2) watt falls normally on a polariser of cross sectional area 3 xx 10^(-4) m^(2) . The polariser rotates with an angular frequency of pi rad/s. The energy of liggt passing through the polariser per revolution will be

A beam of unpolarised light having flux 10^(-2) watt falls normally on a polariser of cross sectional area 3 xx 10^(-4) m^(2) . The polariser rotates with an angular frequency of pi rad/s. The energy of liggt passing through the polariser per revolution will be

A laser beam of 10mW power and wavelength 700nm has aperture of 3mm . If it is focused by a lens of focal length 5cm , the intensity of image is

A beam of plane polarized light having flux 10^(-3) Watt falls normally on polarizer of cross sectional area 3x10^(-4) m^2. Polarizer rotates with angular frequency of 31.4 rad/s. Energy of light passes through the polarizer per resolution will be

A beam of plane polarized light having flux 10^(-3) Watt falls normally on polarizer of cross sectional area 3xx10^(-4) m^2 . Polarizer rotates with angular frequency of 31.4 rad/s. Energy of light passes through the polarizer per revolution will be