The light from the Sun is found to have a maximum intensity near the wavelength of 470 nm. Assuming the surface of the Sun as a black body, the temperature of the Sun is .................
[Wien's constant b = 2 .898 x l0- 3mK]
(a) 5800 K
(b) 6050 K
(c) 6166 K
(d) 6500 K
A pinhole is made in a hollow sphere of radius 5 cm whose inner wall is at temperature 727oC. Find the power radiated per unit area. [Stefan’s constant σ = 5.7 x 10-8 J/m2 s K4 , emissivity (e) = 0.2]
Compute the temperature at which the r.m.s. speed of nitrogen molecules is 832 m/s. [Universal gas constant, R = 8320 J/k mole K, molecular weight of nitrogen = 28.]
The susceptibility of magnesium at 300 K is 2.4 x 10-5. At what temperature will the susceptibility increase to 3.6 x 10-5?
The substance which allows heat radiations to pass through is _______.
(B) water vapour
(D) dry air
A body cools from 62°C to 54°C in 10 minutes and to 48°C in the next 10 minutes. Find the temperature of the surroundings.