Practice Test

Please solve the following questions. This is not a real exam, it will not be graded, and you do not need to submit your solutions to anyone. The questions are simply intended to help you practice for the real exam.

These questions will not appear in the exam itself. Students who don't genuinely attempt to solve the questions on their own, and only memorize the solutions, will have a very hard time in the actual exam!

This sample exam is online, but the real exam will be given in person, at a time and place indicated on the course website.

THIS IS NOT THE ACTUAL EXAM!
THIS IS JUST A PRACTICE EXAM!
THE REAL EXAM IS IN PERSON!

If you need any clarifications for these questions, you can ask for them on the course Teams channel.

Question 1

I live on the 3rd floor, and my friend lives on the 15th floor. If I send a radio wave to my friend, the wave will be...

Blueshifted (my friend will see a shorter wavelength).
Redshifted (my friend will see a longer wavelength).
Unaffected (my friend will see the same wavelength).

Question 2

Which of the following was observed by the Event Horizon Telescope?

Cygnus X-1.
M87*.
PSR B1919+21.

Question 3

What is the difference between the weak equivalence principle and the Einstein equivalence principle?

The weak equivalence principle is formed in terms of mass, while the Einstein equivalence principle is formed in terms of energy.
The weak equivalence principle is formed in terms of mass, while the Einstein equivalence principle is formed in terms of acceleration.
The weak equivalence principle is formed in terms of acceleration, while the Einstein equivalence principle is formed in terms of mass.

Question 4

What was the significance of the gravitational wave event GW150914?

It was the first time gravitational waves were detected directly.
It was the first time both gravitational waves and electromagnetic waves were detected from the same source.
It was the first time a black hole was photographed.

Question 5

In Newtonian mechanics, the speed of light in vacuum...

Is constant and independent of the observer, consistent with the predictions of electromagnetism.
Depends on the observer, in contradiction with the predictions of electromagnetism.
Is constant and independent of the observer, in contradiction with the predictions of electromagnetism.

Question 6

What will be the advantage of putting a gravitational wave detector in space compared to detectors on Earth?

The waves will not be blocked by interstellar dust.
It will be sensitive to waves with much longer wavelengths.
It will be sensitive to waves with much shorter wavelengths.

Question 7

You are jumping from a tree down to the ground. According to the Einstein equivalence principle, while you are falling, you're...

Not in any kind of frame.
In an inertial frame.
In a non-inertial frame.

Question 8

What was the source of the gravitational wave event GW150914?

Two neutron stars merging.
Two black holes merging.
A black hole and a neutron star merging.

Question 9

Which of the following is a stellar black hole?

Cygnus X-1.
PSR B1919+21.
M87*.

Question 10

In the Eddington experiment, why was it important to measure the position of the stars during an eclipse?

Because that was the only time during the year those stars could be seen.
Because that was the only time those stars could be seen next to the Sun.
Because at that time their light is not bent due to the curvature of spacetime.

Question 11

The Newtonian prediction for the perihelion precession of Mercury was...

Correct, because it took into account the curvature of spacetime.
Correct, because the curvature of spacetime is not relevant for this prediction.
Incorrect, because it did not take into account the curvature of spacetime.

Question 12

How did LIGO provide evidence for gravitational waves in 2015?

Indirectly, by observing changes in the orbital period of a binary system.
Directly, by measuring the local influence of the gravitational wave itself on spacetime.
Directly, by detecting electromagnetic emission from the gravitational wave event.

Question 13

What is an Einstein ring?

A light source that is being gravitationally lensed into a circular shape.
A light source that is being gravitationally lensed into 4 distinct copies.
The ring that Einstein gave his first wife.

Question 14

Why don't we notice special-relativistic effects like time dilation in our daily lives?

Because we are moving at speeds much slower than the speed of light.
Because we are moving at speeds much faster than the speed of light.
Because our clocks compensate for these effects.

Question 15

The relative velocity between Alice and Bob corresponds to a Lorentz factor of 5. Alice measures a proper time of 10 seconds between two events. How much time does Bob measure?

10 seconds.
2 seconds.
50 seconds.

Question 16

What makes the expansion of the universe accelerate?

Dark energy.
Dark nebulae.
Dark matter.

Question 17

Before the cosmic microwave background was released, the universe was...

Opaque.
Yellow.
Transparent.

Question 18

Which of the following objects bends spacetime the least?

The Sun.
The Moon.
The Earth.

Question 19

The Schwarzschild radius of a black hole with 10 solar masses is around 30 km. What is the Schwarzschild radius of a black hole with 30 solar masses?

90 km.
150 km.
60 km.

Question 20

Geodesics inside the event horizon...

Can only point away from the center of the black hole.
Can only point toward the center of the black hole.
Can point in any direction.

Question 21

According to observations, stars farther from the center of a galaxy rotate...

At the same speed as stars closer to the center.
Slower than stars closer to the center.
Faster than stars closer to the center.

Question 22

I live on the 24th floor. Compared to my friend who lives on the 12th floor, I experience time...

At a faster rate.
At the same rate.
At a slower rate.

Question 23

How did the Hulse-Taylor pulsar provide evidence for gravitational waves in 1974?

Directly, by measuring the local influence of the gravitational wave itself on spacetime.
Directly, by detecting electromagnetic emission from the gravitational wave event.
Indirectly, by observing changes in the orbital period of a binary system.

Question 24

Galaxy A is half as far from us compared to Galaxy B. According to Hubble's law, this means that Galaxy A...

Moves away from us half as fast compared to Galaxy B.
Moves away from us twice as fast compared to Galaxy B.
Moves away from us at the same speed as to Galaxy B.

Question 25

What is the Einstein cross?

A light source that is being gravitationally lensed into 4 distinct copies.
The cross that Einstein gave his first wife as a Christmas gift.
A light source that is being gravitationally lensed into a circular shape.