Q. The value of acceleration due to gravity on the Moon is approximately:

  • (A) 9.8 m/s²
  • (B) 4.9 m/s²
  • (C) 1.63 m/s²
  • (D) 0.98 m/s²
๐Ÿ“ Notes
โœ… Correct Answer: (C) 1.63 m/s²
Explanation: The acceleration due to gravity on the Moon is about 1/6th that of Earth, i.e., 1.63 m/s².

Q. The force responsible for keeping planets in orbit around the Sun is:

  • (A) Electrostatic force
  • (B) Magnetic force
  • (C) Nuclear force
  • (D) Gravitational force
๐Ÿ“ Notes
โœ… Correct Answer: (D) Gravitational force
Explanation: The gravitational attraction between the Sun and planets keeps the planets in orbit.

Q. The wavelength of visible light lies approximately in the range:

  • (A) 10 nm - 100 nm
  • (B) 100 nm - 400 nm
  • (C) 400 nm - 700 nm
  • (D) 700 nm - 1000 nm
๐Ÿ“ Notes
โœ… Correct Answer: (C) 400 nm - 700 nm
Explanation: Visible light has wavelengths approximately between 400 nm and 700 nm.

Q. Which of the following is not an electromagnetic wave?

  • (A) X-rays
  • (B) Ultrasonic waves
  • (C) Radio waves
  • (D) Gamma rays
๐Ÿ“ Notes
โœ… Correct Answer: (B) Ultrasonic waves
Explanation: Ultrasonic waves are mechanical waves and require a medium for propagation.

Q. The energy of a photon is directly proportional to:

  • (A) Wavelength
  • (B) Square of wavelength
  • (C) Frequency
  • (D) Square of frequency
๐Ÿ“ Notes
โœ… Correct Answer: (C) Frequency
Explanation: According to Planck's equation, E = hν, so energy is directly proportional to frequency.

Q. The terminal velocity of a body falling through a liquid is attained when:

  • (A) Acceleration is maximum
  • (B) Acceleration is zero
  • (C) Velocity is zero
  • (D) Mass becomes zero
๐Ÿ“ Notes
โœ… Correct Answer: (B) Acceleration is zero
Explanation: At terminal velocity, net force acting on the body becomes zero, so acceleration is zero.

Q. A concave mirror can form:

  • (A) Only virtual images
  • (B) Only real images
  • (C) Both real and virtual images
  • (D) Neither real nor virtual images
๐Ÿ“ Notes
โœ… Correct Answer: (C) Both real and virtual images
Explanation: A concave mirror forms real images when the object is beyond focus and virtual images when it is between focus and pole.

Q. The work done by gravity while moving a body in a closed path is:

  • (A) Positive
  • (B) Negative
  • (C) Zero
  • (D) Infinite
๐Ÿ“ Notes
โœ… Correct Answer: (C) Zero
Explanation: Gravity is a conservative force, so the net work done in a closed path is zero.

Q. The dimensions of angular momentum are:

  • (A) [MLT^-1]
  • (B) [ML²T^-1]
  • (C) [ML²T^-2]
  • (D) [ML^-1T^-1]
๐Ÿ“ Notes
โœ… Correct Answer: (B) [ML²T^-1]
Explanation: Angular momentum = r × p = [L] × [MLT^-1] = [ML²T^-1].

Q. The image formed by a convex 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 convex mirror always forms a virtual, erect and diminished image.

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