Multiple Choice

What was the purpose of the Michelson–Morley experiment?

1. To determine the exact speed of light
2. To analyze the electromagnetic spectrum
3. To establish that Earth is the true frame of reference
4. To learn how the ether affected the propagation of light

In 2003, Earth and Mars were aligned so that Earth was between Mars and the sun. Earth and Mars were 5.6×10⁷ km from each other, which was the closest they had been in 50,000 years. People looking up saw Mars as a very bright red light on the horizon. If Mars was 2.06×10⁸ km from the sun, how long did the reflected light people saw take to travel from the sun to Earth?

1. 14 min and 33 s
2. 12 min and 15 s
3. 11 min and 27 s
4. 3 min and 7 s

What does this expression represent: $\frac{1}{\sqrt{1-\frac{u^2}{c^2}}}$

1. time dilation
2. relativistic factor
3. relativistic energy
4. length contraction

What is the rest energy, E₀, of an object with a mass of 1.00 g ?

1. 3.00×10⁵ J
2. 3.00×10¹¹ J
3. 9.00×10¹³ J
4. 9.00×10¹⁶ J

The fuel rods in a nuclear reactor must be replaced from time to time because so much of the radioactive material has reacted that they can no longer produce energy. How would the mass of the spent fuel rods compare to their mass when they were new? Explain your answer.

1. The mass of the spent fuel rods would decrease.
2. The mass of the spent fuel rods would increase.
3. The mass of the spent fuel rods would remain the same.
4. The mass of the spent fuel rods would become close to zero.