51. Space-time can be pictured as:
- a closed box
- a rigid steel block
- a flexible sheet that can bend
- a straight line
Answer: C) a flexible sheet that can bend
Explanation: Rubber-sheet analogy. SLO P-11-F-06 · Knowledge
MCQs / Physics / Special Relativity
Special Relativity MCQs — Physics (page 3)
90 multiple-choice questions on Special Relativity from Physics, each with the correct answer and, where available, a teacher's explanation. Read through them to revise the chapter, then practise the same questions one by one to test yourself.
52. Black holes are regions where space-time is:
- curved so strongly that light cannot escape
- filled with light
- absent
- flat
Answer: A) curved so strongly that light cannot escape
Explanation: Extreme curvature. SLO P-11-F-06 · Knowledge
53. Length contraction happens:
- perpendicular to motion only
- only along the direction of motion
- in all directions
- never
Answer: B) only along the direction of motion
Explanation: Perpendicular dimensions are unchanged. SLO P-11-F-03 · Understanding
54. Proper length is the length of an object measured:
- at the speed of light
- by a moving observer
- in its own rest frame
- in a gravitational field
Answer: C) in its own rest frame
Explanation: Longest measured length. SLO P-11-F-03 · Understanding
55. Two observers moving relative to each other each see the other's clock running:
- at the same rate
- stopped
- slow
- fast
Answer: C) slow
Explanation: Symmetric effect. SLO P-11-F-03 · Understanding
56. Newton's first law holds true in:
- all frames
- inertial frames only
- non-inertial frames only
- no frames
Answer: B) inertial frames only
Explanation: In accelerating frames, objects seem to accelerate without a force. SLO P-11-F-01 · Understanding
57. A rod of proper length 10 m moves at 0.99c along its length. An observer at rest measures its length as:
- 14.1 m
- 1.41 m
- 0.705 m
- 2.82 m
Answer: B) 1.41 m
Explanation: L = L0 1 - v^2/c^2 = 10 1 - 0.99^2 = 1.41 m. SLO P-11-F-05 · Understanding
58. The constancy of the speed of light means that:
- time is absolute
- velocities cannot simply be added as in Newtonian mechanics at high speeds
- light has no speed
- space is absolute
Answer: B) velocities cannot simply be added as in Newtonian mechanics at high speeds
Explanation: Leads to new velocity rules. SLO P-11-F-02 · Understanding
59. If the speed of light is constant for all observers, then:
- measurements of time and length must depend on the observer's motion
- light must slow down
- time must be absolute
- lengths must be absolute
Answer: A) measurements of time and length must depend on the observer's motion
Explanation: Something has to give. SLO P-11-F-03 · Understanding
60. GPS satellites must correct for relativity because:
- they move faster than light
- they have no clocks
- their clocks run at a different rate from clocks on Earth
- light doesn't reach them
Answer: C) their clocks run at a different rate from clocks on Earth
Explanation: Otherwise positions drift by kilometres per day. SLO P-11-F-03 · Understanding
61. Light passing close to the Sun bends because:
- the Sun repels light
- light is slowed by sound
- light has electric charge
- space-time is curved near the Sun
Answer: D) space-time is curved near the Sun
Explanation: Gravitational lensing; confirmed in 1919. SLO P-11-F-06 · Knowledge
62. General relativity (1915) extends special relativity to include:
- only electricity
- gravity and accelerating frames
- only light
- nothing new
Answer: B) gravity and accelerating frames
Explanation: Curved space-time. SLO P-11-F-04 · Knowledge
63. A ball on the floor of a plane that is accelerating for take-off:
- rolls towards the front
- rises to the ceiling
- stays at rest
- rolls towards the back
Answer: D) rolls towards the back
Explanation: Non-inertial frame. SLO P-11-F-01 · Understanding
64. A body of rest mass 9.11 10^-31 kg moves at 0.8c. Its relativistic mass is:
- 7.59 10^-31 kg
- 1.52 10^-29 kg
- 3.04 10^-30 kg
- 1.52 10^-30 kg
Answer: D) 1.52 10^-30 kg
Explanation: m = gamma m0 = m0 1 - v^2/c^2 = 1.52 10^-30 kg. SLO P-11-F-05 · Understanding
65. A train moving at constant velocity on a straight track is:
- a non-inertial frame
- not a frame of reference
- a rotating frame
- an inertial frame
Answer: D) an inertial frame
Explanation: No acceleration. SLO P-11-F-01 · Understanding
66. Special relativity deals with:
- accelerating frames only
- inertial frames moving at constant velocity relative to each other
- frames at rest only
- rotating frames
Answer: B) inertial frames moving at constant velocity relative to each other
Explanation: 'Special' = inertial frames. SLO P-11-F-01 · Understanding
67. The first postulate of special relativity states that:
- mass is always conserved
- time is absolute
- the speed of light depends on the source
- the laws of physics are the same in all inertial frames
Answer: D) the laws of physics are the same in all inertial frames
Explanation: Principle of relativity. SLO P-11-F-04 · Knowledge
68. A car braking hard is:
- a non-inertial frame
- an inertial frame
- a frame where no forces act
- at rest
Answer: A) a non-inertial frame
Explanation: It is decelerating. SLO P-11-F-01 · Understanding
69. Maxwell's equations of electromagnetism predicted that light travels at:
- the speed of sound
- a fixed speed c
- a speed that depends on the observer
- infinite speed
Answer: B) a fixed speed c
Explanation: Einstein made this a postulate. SLO P-11-F-02 · Understanding
70. The speed of light is a universal constant because it is:
- the speed of electrons
- measured on Earth only
- the fastest sound
- the same in all inertial frames
Answer: D) the same in all inertial frames
Explanation: Invariance. SLO P-11-F-02 · Understanding
71. Space and time combine into a four-dimensional:
- energy-momentum
- field
- space-time
- vacuum
Answer: C) space-time
Explanation: Minkowski space-time. SLO P-11-F-03 · Understanding
72. In space-time, two observers in relative motion:
- can disagree on separate distances and times but agree on the space-time interval
- see no events
- disagree on everything
- agree on all distances and times
Answer: A) can disagree on separate distances and times but agree on the space-time interval
Explanation: Invariant interval. SLO P-11-F-06 · Knowledge
73. A non-inertial frame of reference is one that:
- is at rest
- is accelerating
- moves with constant velocity
- moves in a straight line at constant speed
Answer: B) is accelerating
Explanation: Includes rotating frames. SLO P-11-F-01 · Understanding
74. According to special relativity, no material object can travel:
- in a straight line
- faster than sound
- at or faster than the speed of light
- at constant velocity
Answer: C) at or faster than the speed of light
Explanation: c is the universal speed limit. SLO P-11-F-02 · Understanding
75. In Newtonian physics time is absolute, but in relativity time is:
- relative (depends on the observer)
- infinite
- zero
- also absolute
Answer: A) relative (depends on the observer)
Explanation: Relativity of time. SLO P-11-F-03 · Understanding
Practise Special Relativity MCQs
More Physics chapters
- Physical Quantities and Measurement MCQs
- Motion MCQs
- Vectors MCQs
- Electricity MCQs
- Kinematics and Projectile Motion MCQs
- Circular and Rotational Motion MCQs
- Momentum and Collisions MCQs
- Deformation of Solids MCQs
- Work and Energy MCQs
- Fluid Statics and Dynamics MCQs
- Kinetic Theory and First Law of Thermodynamics MCQs
- Heat Engines, Second Law and Entropy MCQs