Assuming that the temperature at the surface of the Sun is 6000 K, find out the size of a virtual star (in terms of the size of Sun) whose surface temperature is 3000 K and the power radiated by the virtual star is 25 times the power radiated by the Sun. Treat both, the Sun and virtual star as a blackbody.

If the surface temperature of the sun is assumed to be 6150 K, find the wave length of maximum intensity in the sun’s radiation taking Wien's constant 2.88 xx 10^-3mk .

Assuming that the sun radiates as a black body, calculate the energy radiated per minute by unit area of its surface. Surface temperature of the sun = 5727^@C and Stefan's constant = 5.7 xx10^-8 Jm^-2K^-4s^-1 .

Analysis of the sun's spectrum shows that the wave length of maximum intensity is 4750 A^@ . Taking Wien's constant as 2.9 xx 10^-3 mk , find the surface temperature of the sun.

Earth's mean temperature can be assumed to be 280K. How will the curve of blackbody radiation look like for this temperature? Find out lambda_max , in which part of the electromagnetic spectrum, does this value lie?

Apparatus: Two aluminium tins of the same size, two small galsses, water, thermometers, black paint, etc. : Procedure: Paint the outer surface of one tin black paint, and let it dry. Then in both tins, place one glass, each filled with water at the same temperature. cover the tins with lids. Keep them in the sun for two hours. Now measure the temperature of the water in the glasses in the two tins. What is the reason for the difference in the temperature?

The intensity of radiation emitted by the sun has its maximum value at a wavelength of 510 nm and that emitted by the North star has the maximum value at 350 nm. If these stars behave like black bodies, then the ratio of the surface temperatures of the sun and the north star is

If lambdam for solar radiation is 4753A^@ , estimate the surface temperature of the sun. Wien's constant, b = 0.2893 cmk.

Questions based on paragraph : One way of classifying stars is on the basis of their temperature . In the order of decreasing temperature , stars are divided into seven main types viz , O ,B,A,F,G,K and M . : Which star type would our sun belong ?:

If we consider solar system consisting of the earth and sun only as one of the ideal thermodynamic system. The sun works as source of energy having temperature 6000K and the earth as sink having temperature 300K , the efficiency of solar system would be on the basis of exchange of radiations