# IB Physics Relativity

A tutorial sheet of true-false questions on relativity is given below.

1. The speed of light (according to the local observer) near a black hole is 3.0x108 m/s. A distant observer considers the speed of light to be much less than this.
2. The speed of light changes (according to a distant observer) as it passes through a gravitational field.
3. The speed of light is the same for all observers in a flat space.
4. Space can expand at a rate greater than c.
5. Nothing can escape from inside a black hole.
6. Particles can escape from the event horizon of a black hole.
7. Light leaving the horizon of a black hole undergoes a gravitational red shift and has an infinite wavelength at infinity and so cannot be detected.
8. The time coordinate of an event is the same value at all locations in the same inertial reference frame.
9. If an event occurs at x' at time t' in the inertial reference frame S' the event occurs at time ɣ(t' + v x'/c2) in another inertial frame S.
10. The proper time interval is the least time interval between two events as reckoned from any inertial reference frame.
11. The proper time interval is the time interval between two events in the inertial reference frame where the events occur at the same position.
12. The proper length of a rod is the length of the rod in the inertial reference frame where the rod is at rest.
13. The rest reference frame for a moving object is the reference frame in which the object is at rest.
14. On a spacetime diagram the units on each axis have the same scale.
15. On a spacetime diagram the worldline of a particle of non-zero rest mass cannot have a gradient less than 1.
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