1. Which of the following will two observers in inertial reference frames always agree on? (Choose all that apply.)
(a) The time an event occurred.
(b) The distance between two events.
(c) The time interval between the occurrence of two events.
(d) The speed of light.
(e) The validity of the laws of physics.
(f) The simultaneity of two events.
2. Two observers in different inertial reference frames moving relative to each other at nearly the speed of light see the same two events but, using precise equipment, record different time intervals between the two events. Which of the following is true of their measurements?
(a) One observer is incorrect, but it is impossible to tell which one.
(b) One observer is incorrect, and it is possible to tell which one.
(c) Both observers are incorrect.
(d) Both observers are correct.