A spherical black body of radius 12 cm radiates 450 W power at 500 K. If the radius is reduced to half and temperature is doubled. find the power- radiated in watt.

A spherical blackbody of 12 cm radius used to emit 540 w thermal energy at 500 k temperature.. If the radius is halved and temperature is doubled then what will be the radiant energy?

A spherical blackbody of radius 12 cm at 5000 K temperature emits 540 watt thermal power. Find out the emitted power if its radius being half & temperature being doubled.

The power radiated by a black body is P and it radiates maximum energy at wavelength, lambda_(0) . If the temperature of the black body is now changed so that it radiates maximum energy at wavelength (3)/(4)lambda_(0) , the power radiated by it becomes nP. The value of n is

A wire of length 1 m and radius 10^(-3) m is carrying a heavy current and is assumed to radiate as a black body. At equilibrium its temperature is 900 K while that of the surroundings is 300 K. The resistivity of the material of the wire at 300 K is pi^2xx10^(-8)Omega-m and its temperature coefficient of resistance is 7.8xx10^(-3)per@_C (Stefan's constant =5.68xx10^(-8)W-m^2-K^4) . So, the current in the wire is

A cylinder of radius 12 cm contains water to a depth of 20 cm. When a spherical iron ball is dropped in to the cylinder, the level of water is raised by 6.75 cm. Find the radius of the ball. [pi = (22)/(7)]