JEE Main Physics Questions - Page 6

51. A Carnot engine works between 300 K and 600 K. Its efficiency is:

A) 25% B) 50% C) 75% D) 100%

52. If the absolute temperature of a gas is increased 4 times, the root mean square (rms) speed of its molecules becomes:

A) 4 times B) 2 times C) 16 times D) Half

53. The mean free path ÃƒÅ½Ã‚Â» of gas molecules is inversely proportional to:

A) Temperature B) Pressure C) Square of the molecular diameter D) Both B and C

54. A monatomic gas molecule has how many degrees of freedom?

A) 3 B) 5 C) 6 D) 2

55. The period of a simple pendulum is T. If the length of the pendulum is increased by 21%, the percentage increase in the period is:

A) 10% B) 21% C) 11% D) 42%

56. In simple harmonic motion, the potential energy is maximum at:

A) Mean position B) Extreme positions C) Halfway between mean and extreme D) Nowhere (it is constant)

57. A source of sound of frequency 600 Hz is moving towards a stationary observer with a speed of 30 m/s. The frequency heard by the observer is (speed of sound = 330 m/s):

A) 660 Hz B) 550 Hz C) 600 Hz D) 700 Hz

58. The distance between a node and an adjacent antinode in a stationary wave is:

A) ÃƒÅ½Ã‚Â» B) ÃƒÅ½Ã‚Â»/2 C) ÃƒÅ½Ã‚Â»/4 D) ÃƒÅ½Ã‚Â»/8

59. The speed of sound is maximum in:

A) Steel B) Water C) Air D) Vacuum

60. If the intensity of sound is increased by a factor of 100, the increase in intensity level in decibels (dB) is:

A) 10 dB B) 20 dB C) 100 dB D) 40 dB

JEE Main Physics MCQs - Part 6