Q. The efficiency of an ideal machine is:

  • (A) 50%
  • (B) 75%
  • (C) 100%
  • (D) 150%
๐Ÿ“ Notes
โœ… Correct Answer: (C) 100%
Explanation: An ideal machine has no energy loss, so its efficiency is 100%.

Q. Which of the following is not a fundamental force?

  • (A) Gravitational force
  • (B) Electromagnetic force
  • (C) Frictional force
  • (D) Strong nuclear force
๐Ÿ“ Notes
โœ… Correct Answer: (C) Frictional force
Explanation: Frictional force is a macroscopic force arising due to electromagnetic interactions and is not fundamental.

Q. The dimensional formula of gravitational constant G is:

  • (A) [Mโป¹L³Tโป²]
  • (B) [ML²Tโป²]
  • (C) [MLTโป²]
  • (D) [MโฐL³Tโป²]
๐Ÿ“ Notes
โœ… Correct Answer: (A) [Mโป¹L³Tโป²]
Explanation: From Newton's law of gravitation, G = Fr²/(mโ‚mโ‚‚), giving dimensions [Mโป¹L³Tโป²].

Q. The energy possessed by a body due to its position is called:

  • (A) Kinetic energy
  • (B) Potential energy
  • (C) Thermal energy
  • (D) Mechanical advantage
๐Ÿ“ Notes
โœ… Correct Answer: (B) Potential energy
Explanation: Potential energy is the energy stored in a body due to its position or configuration.

Q. Which scientist proposed the quantum theory of radiation?

  • (A) Albert Einstein
  • (B) Niels Bohr
  • (C) Max Planck
  • (D) Erwin Schrödinger
๐Ÿ“ Notes
โœ… Correct Answer: (C) Max Planck
Explanation: Max Planck proposed the quantum theory in 1900, stating that energy is emitted in discrete packets called quanta.

Q. The angular momentum of a body is conserved when:

  • (A) Net force is zero
  • (B) Net torque is zero
  • (C) Velocity is constant
  • (D) Acceleration is zero
๐Ÿ“ Notes
โœ… Correct Answer: (B) Net torque is zero
Explanation: Angular momentum remains conserved if the net external torque acting on the system is zero.

Q. A body of mass 5 kg is lifted to a height of 10 m. The potential energy gained is (g = 10 m/s²):

  • (A) 50 J
  • (B) 100 J
  • (C) 500 J
  • (D) 1000 J
๐Ÿ“ Notes
โœ… Correct Answer: (C) 500 J
Explanation: Potential energy = mgh = 5 × 10 × 10 = 500 J.

Q. The number of significant figures in 0.004560 is:

  • (A) 3
  • (B) 4
  • (C) 5
  • (D) 6
๐Ÿ“ Notes
โœ… Correct Answer: (B) 4
Explanation: Leading zeros are not significant. The digits 4, 5, 6 and the trailing zero are significant.

Q. The escape velocity on Earth is approximately:

  • (A) 5.6 km/s
  • (B) 7.9 km/s
  • (C) 11.2 km/s
  • (D) 16.8 km/s
๐Ÿ“ Notes
โœ… Correct Answer: (C) 11.2 km/s
Explanation: The escape velocity from Earth's surface is about 11.2 km/s.

Q. The dimensional formula of impulse is:

  • (A) [MLTโป²]
  • (B) [MLTโป¹]
  • (C) [ML²Tโป²]
  • (D) [ML²Tโป¹]
๐Ÿ“ Notes
โœ… Correct Answer: (B) [MLTโป¹]
Explanation: Impulse = Force × Time = [MLTโป²] × [T] = [MLTโป¹].

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