Class 11 Physics · Chapter 11 · Test 2
Time Dilation and E=mc²
30 MCQs This test covers time dilation, length contraction and relativistic mass with their formulas and numericals. It also covers mass-energy equivalence, kinetic energy, space-time curvature, light bending and gravitational waves.
30 questions · 25 min · 30 marks
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Sample questions
The first 5 of 30. Try each one, then tap to see the answer.
Question 1
In relativity the time interval measured by an observer at rest relative to the events is called:
- ADilated time
- BProper time
- CRelative time
- DContracted time
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Answer: B
This is the proper time t0.
Question 2
The time interval measured by an observer moving relative to the events is:
- At = t0 sqrt(1 - v^2/c^2)
- Bt = t0 / sqrt(1 - v^2/c^2)
- Ct = t0
- Dt = t0 (1 - v/c)
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Answer: B
t = t0 / sqrt(1 - v^2/c^2) which is greater than t0.
Question 3
Moving clocks run:
- AFaster
- BSlower
- CAt the same rate
- DBackward
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Answer: B
Time is dilated for objects in relative motion.
Question 4
The factor sqrt(1 - v^2/c^2) is always:
- AGreater than 1
- BLess than 1
- CEqual to 1
- DNegative
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Answer: B
For v < c it is less than one so t is greater than t0.
Question 5
A pendulum has a period of 3.0 s in its own frame. For an observer moving at 0.95c relative to it the period is about:
- A0.94 s
- B3.0 s
- C9.6 s
- D2.9 s
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Answer: C
t = 3.0 / sqrt(1 - 0.9025) = 9.6 s.
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