W.B Joint Entrance Exam
1. Experimental investigations show that the intensity of solar radiation is maximum for a wavelength 480 nm in the visible region. Estimate the surface temperature of sun. Given Wein’s constant b = 2.88 × 10–3 mK., 2. The temperature of an ideal gas is increased from 120 K to 480 K. If at 120 K, the root mean square speed of gas molecules is v, then at 480 K it will be...
1. One Kg of copper is drawn into a wire of 1mm diameter and a wire of 2 mm diameter. The resistance of the twowires will be in the ratio (A) 2 : 1 (B) 1 : 2 (C) 16 : 1 (D) 4 : 1, 2. An electrical cable having a resistance of 0.2 Ω delivers 10kw at 200V D.C. to a factory. What is the efficiency of transmission ?..