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One mole of an ideal gas undergoes isothermal expansion to double its initial volume
at 100°C. In terms of the universal gas constant R, the amount of work done on the
gas is approximately

‎पि‏ 10015 )0 3731127 )© 168 (م 1168ھ

‎A gas mixture at a temperature T consists of three gases denoted 1, 2 and 3. If their
molecular masses are related by m, > Mz > Mg, their rms velocities are related by

‎A) (Vims)1 > Vims)2 > 793
8) (೪7915 (7027 (793
0) (7017 (7925 703
D) (Yims)1 < Vims)2 < 793

‎In adouble slit experiment, the fringe width is found to be f for red light. If the distance
between the slits is doubled and blue light is used, then

‎A) B increases
8) B decreases
0

‎)

‎D) Data insufficient to calculate change in B

‎B remains unchanged

‎The refractive index for a material is /3. When a block of the material is placed in
air, the Brewster angle for the air — material pair will be

‎A) 15° B) 30° C) 45° D) 60°

‎The type of pumping mechanism employed in a Ruby Laser is
A) Electrical B) Chemical
C) Optical D) Thermal

‎Which of the following is incorrect regarding the spectra produced by a prism and
by a diffraction grating ?

‎A) The spectrum from a prism is more intense
B) Ina prism spectrum, red is deviated more

‎C) There is only a single spectrum from a prism whereas there are more than one
spectra from a grating

‎D) Prism uses dispersion whereas grating uses diffraction to produce spectrum

‎-7-