141 Two samples A and B of a certain gas, which are initially at the same temperature pressure, are compressed from volume V to V/2 .A is compressed isothermally, whilecompressed adiabatically. The final pressure of A is –
(A) more than that of B
(B) equal to that of B
(C) less than that of B
(D) twice that of B
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142 When 20J of work is done on a gas, 40.J of heat energy is released iv of the gas was 70 J, what is the final internal energy ?
(A) -150J
(B) 50 J
(C) 90J
(D) 110J
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143 An ideal heat engine operates in a Carnot cycle between 227°C and 127°C. It absorbs 10 tmperature. The amount of heat converted to work is –
(A) 2000 J
(B) 4000 J
(C) 8000 J
(D) 5600 J
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144 The efficiencies of all reversible heat engines working between same temperature –
(A) are same.
(B) depend on fuel used.
(C) depend on pressure.
(D) depend on volume.
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145 In simple harmonic motion, at which value of displacemen, kinetic energy is equal to potential energy (a is the amplitude)?
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146 A child is sitting on a swing. Its minimum and maximum heights from the ground are 0.75 m and 2 m respectively. Its maximum speed will be –
(A) 10 m/s
(B) 5 m/s
(C) 8 m/s
(D) 15 m/s
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147 A 5 kg collar is attached to a spring of force constant 500 Nm-1. It slides without on a horizontal rod as shown in the figure. The collar is displaced in position by 10.0 cm and released. The period of oscillation of the collar is-
(A) 6.28 s
(B) 62.8 s
(C) 0.0628 s
(D) 0.628 s
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148 The right relationship between the square of space ofspeed of sound (v2) and absolute temp (T) of any gas in gaseous medium –
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149 Velocity of source of sound, when to a stationary observer the frequency appea double the original frequency (velocity of sound = 330 ms--1) is –
(A) 330 ms-1
(B) 165 ms-1
(C) -330 ms-1
(D) -165 ms-1
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150 In two identical tubes A and B, tube A has both ends open, while tube B has one end The ratio of fundamental frequency of tubes A and B is (A : B) –
(A) 1 : 2
(B) 1 : 4
(C) 2 : 1
(D) 4 : 1
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