Question

Hi please solve all of these physics problems on the sheet. Thank you.

601 The temperature of an object is best described as the a) heat content of the object. b) heat transferred to the material. e) total kinetic energy per kilogram of material d)average random kinetic energy per particle. 61] Compared to a blue star in the same local cluster, the surface temperature of a red star is a) greater. b) the same. c) lower. d) not consistently any of these 621 A spherical perfect black body of radius R at absolute temperature T radiates energy at a rate (power) which is proportional to a)R' and T. b) R' and T d) R' and T e) R and T [63] For any system or process, the sum of the work done on the system and the heat flow into the system is b) the change in internal energy d) none of these a) zero. c) always greater than zero. [64] Which of the following are correct for an adiabatic compression? Mark all correct answers. a) Heat is not lost from the system. c) Temperature increases more than for a constant pressure compression d) The final pressure is lower than isothermal for the same volume change. e) The entropy change for the sample is zero. b) Pressure increases (65] On a pressure-volume diogram, the work gone on a gas sample during a cyclic process is equal to a) The orea enclosed by the diagram. b) The perimeter of the cycle c) The area between the highest leg of the cycle and the volume axis. ) The product of the largest values of pressure and volume i in the cycle Math Modeis (66) Light is travelling inside a 2 mm thick planar sheet of transparent plastic, moving outword from the center but trapped inside the sheet by total internal reflection. The intensity of the light at a point in the sheet is proportional to a)r b) 1/ c) 1/r d) Intr) e) none of these.

Answer 1

60 d

From kinetic theory of gases

From kinetic theory of gases 1/2 mv^2 = 3KT/m K is the boltzmann constant From wiens displacement law lambda T = constant The red wavelength is larger than blue and hence temperature has to be larger. Stefans law states that the power per unit area emmitted by a black body is proportional to the fourth power of its temperature. Then total power is proportional to surface area as well. That is 4 pi R^2. Hence the answer DBJ. c is wrong since for adiabatic process TV^gamma - 1 = constant where as V/T = constant for constant pressure process. Others can be proved correct.

K is the boltzmann constant

61 c

From wiens displacement law

The red wavelength is larger than blue and hence temperature has to be larger.

62 d

Stefans law states that the power per unit area emmitted by a black body is proportional to the fourth power of its temperature. Then total power is proportional to surface area as well. That is . Hence the answer.

64 a,b,d,e

c is wrong since for adiabatic process where as for constant pressure process. Others can be proved correct.

65 a