Q. Which law states that the induced emf opposes the change causing it?

  • (A) Faraday's Law
  • (B) Ampere's Law
  • (C) Lenz's Law
  • (D) Gauss's Law
๐Ÿ“ Notes
โœ… Correct Answer: (C) Lenz's Law
Explanation: Lenz's Law states that the induced emf always opposes the change in magnetic flux that produces it.

Q. The kinetic energy of a body becomes four times when its velocity is:

  • (A) Doubled
  • (B) Halved
  • (C) Tripled
  • (D) Quadrupled
๐Ÿ“ Notes
โœ… Correct Answer: (A) Doubled
Explanation: Kinetic energy K = 1/2 mv². If velocity doubles, kinetic energy becomes four times.

Q. The image formed by a plane mirror is always:

  • (A) Real and inverted
  • (B) Virtual and erect
  • (C) Real and erect
  • (D) Virtual and inverted
๐Ÿ“ Notes
โœ… Correct Answer: (B) Virtual and erect
Explanation: A plane mirror always forms a virtual, erect image of the same size as the object.

Q. Which color deviates the most when white light passes through a prism?

  • (A) Red
  • (B) Yellow
  • (C) Green
  • (D) Violet
๐Ÿ“ Notes
โœ… Correct Answer: (D) Violet
Explanation: Violet light has the shortest wavelength and therefore undergoes maximum deviation.

Q. The dimensional formula of pressure is:

  • (A) [MLโป¹Tโป²]
  • (B) [MLTโป²]
  • (C) [ML²Tโป²]
  • (D) [MโฐLTโป²]
๐Ÿ“ Notes
โœ… Correct Answer: (A) [MLโป¹Tโป²]
Explanation: Pressure = Force/Area = [MLTโป²]/[L²] = [MLโป¹Tโป²].

Q. According to Ohm's law, the ratio V/I is:

  • (A) Current
  • (B) Resistance
  • (C) Power
  • (D) Charge
๐Ÿ“ Notes
โœ… Correct Answer: (B) Resistance
Explanation: Ohm's law states V = IR, therefore V/I = R, which is resistance.

Q. The SI unit of magnetic field is:

  • (A) Weber
  • (B) Henry
  • (C) Tesla
  • (D) Gauss
๐Ÿ“ Notes
โœ… Correct Answer: (C) Tesla
Explanation: The SI unit of magnetic field (B) is Tesla (T).

Q. A body of mass 2 kg moving with velocity 3 m/s has momentum:

  • (A) 1.5 kg m/s
  • (B) 5 kg m/s
  • (C) 6 kg m/s
  • (D) 9 kg m/s
๐Ÿ“ Notes
โœ… Correct Answer: (C) 6 kg m/s
Explanation: Momentum p = mv = 2 × 3 = 6 kg m/s.

Q. The frequency of AC mains supply in India is:

  • (A) 25 Hz
  • (B) 50 Hz
  • (C) 60 Hz
  • (D) 100 Hz
๐Ÿ“ Notes
โœ… Correct Answer: (B) 50 Hz
Explanation: The standard frequency of alternating current supplied in India is 50 Hz.

Q. The refractive index of a medium is maximum for:

  • (A) Red light
  • (B) Yellow light
  • (C) Green light
  • (D) Violet light
๐Ÿ“ Notes
โœ… Correct Answer: (D) Violet light
Explanation: The refractive index increases as wavelength decreases, hence it is maximum for violet light.

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