Question 1

A consequence of Einstein's theory of relativity is:

Accepted Answer

A) moving clocks appear to run faster than when they are at rest 
B) moving rods appear shorter than when they are at rest 
C) light has both wave and particle properties 
D) the laws of physics must appear the same to all observers moving with uniform velocity relative to each other 
E) everything is relative 
A) moving clocks appear to run faster than when they are at rest 
B) moving rods appear shorter than when they are at rest 
C) light has both wave and particle properties 
D) the laws of physics must appear the same to all observers moving with uniform velocity relative to each other 
E) everything is relative

Question 2

Two electrons move in opposite directions at 0.70c as measured in the laboratory.The speed of one electron as measured from the other is:

Accepted Answer

A) 0.35c 
B) 0.70c 
C) 0.94c 
D) 1.00c 
E) 1.40c 
A) 0.35c 
B) 0.70c 
C) 0.94c 
D) 1.00c 
E) 1.40c

Question 3

A millionairess was told in 1992 that she had exactly 15 years to live.However, if she immediately takes off, travels away from the Earth at 0.8 c and then returns at the same speed, the last New Year's Day the doctors expect her to celebrate is:

Accepted Answer

A) 2001 
B) 2003 
C) 2007 
D) 2017 
E) 2033 
A) 2001 
B) 2003 
C) 2007 
D) 2017 
E) 2033

Question 4

According to the theory of relativity:

Accepted Answer

A) moving clocks run fast 
B) energy is not conserved in high speed collisions 
C) the speed of light must be measured relative to the ether 
D) momentum is not conserved in high speed collisions 
E) none of the above 
A) moving clocks run fast 
B) energy is not conserved in high speed collisions 
C) the speed of light must be measured relative to the ether 
D) momentum is not conserved in high speed collisions 
E) none of the above

Question 5

The length of a meter stick moving at 0.95c in the direction of its length with respect to the laboratory is measured by simultaneously marking its ends on an axis which is stationary in the laboratory.As measured by clocks moving with the stick, the time interval between the making of the back mark and the making of the front mark is:

Accepted Answer

A) 0 s 
B) 1.1 *10-9 s 
C) 3.2*10-9 s 
D) 3.5* 10-9 s 
E) 1.1 *10-8 s 
A) 0 s 
B) 1.1 *10-9 s 
C) 3.2*10-9 s 
D) 3.5* 10-9 s 
E) 1.1 *10-8 s

Question 6

A certain particle has a kinetic energy of 3.2 *10-10 J and a momentum of 1.7 * 10-18 kg. m/s.Its mass is:

Accepted Answer

A) 9.1 * 10-31 kg 
B) 2.7 * 10-27 kg 
C) 4.5 *10-27 kg 
D) 6.3 *10-27 kg 
E) 8.6*10-27 kg 
A) 9.1 * 10-31 kg 
B) 2.7 * 10-27 kg 
C) 4.5 *10-27 kg 
D) 6.3 *10-27 kg 
E) 8.6*10-27 kg

Question 7

While emitting light of proper frequency f0, a source moves to the right with speed c/4 relative to reference frame S.A detector, to the left of the source, measures the frequency to be f, which is greater than f0.This means:

Accepted Answer

A) the detector is moving to the right with a speed that is greater than c/4 relative to S 
B) the detector is moving to the right with a speed that is less than c/4 relative to S 
C) the detector is moving to the left with a speed that is greater than c/4 relative to S 
D) the detector is moving to the left with a speed that is less than c/4 relative to S 
E) the detector is not moving 
A) the detector is moving to the right with a speed that is greater than c/4 relative to S 
B) the detector is moving to the right with a speed that is less than c/4 relative to S 
C) the detector is moving to the left with a speed that is greater than c/4 relative to S 
D) the detector is moving to the left with a speed that is less than c/4 relative to S 
E) the detector is not moving

Question 8

Two events occur simultaneously on the x axis of reference frame S, one at x = -a and the other at x = +a.According to an observer moving in the positive x direction:

Accepted Answer

A) the event at x = +a occurs first 
B) the event at x = -a occurs first 
C) either event might occur first, depending on the value of a and the observer's speed 
D) the events are simultaneous 
E) none of the above 
A) the event at x = +a occurs first 
B) the event at x = -a occurs first 
C) either event might occur first, depending on the value of a and the observer's speed 
D) the events are simultaneous 
E) none of the above

Question 9

The magnitude of the momentum of a particle can never exceed:

Accepted Answer

A) mc, where m is its mass 
B) E/c, where E is its energy 
C) K/c, where K is its kinetic energy 
D) none of the above, but there is an upper limit 
E) none of the above; there is no upper limit 
A) mc, where m is its mass 
B) E/c, where E is its energy 
C) K/c, where K is its kinetic energy 
D) none of the above, but there is an upper limit 
E) none of the above; there is no upper limit

Question 10

The velocity of an electron is changed from c/2 in the -x direction to c/2 in the +x direction.As a result, its kinetic energy changes by:

Accepted Answer

A) 2mc2 
B)    mc2 
C) mc2 
D) 0.5mc2 
E) 0 
A) 2mc2 
B)    mc2 
C) mc2 
D) 0.5mc2 
E) 0

Question 11

Light from a stationary spaceship is observed, then the spaceship moves directly away from the observer at high speed.As a result, the light seen by the observer has:

Accepted Answer

A) a higher frequency and a longer wavelength than before 
B) a lower frequency and a shorter wavelength than before 
C) a higher frequency and a shorter wavelength than before 
D) a lower frequency and a longer wavelength than before 
E) the same frequency and wavelength as before 
A) a higher frequency and a longer wavelength than before 
B) a lower frequency and a shorter wavelength than before 
C) a higher frequency and a shorter wavelength than before 
D) a lower frequency and a longer wavelength than before 
E) the same frequency and wavelength as before

Question 12

A meson when at rest decays 2 $\mu$s after it is created.If moving in the laboratory at 0.99c, its lifetime according to laboratory clocks would be:

Accepted Answer

A) the same 
B) 0.28$\mu$s 
C) 4.6 $\mu$s 
D) 14$\mu$s 
E) none of these 
A) the same 
B) 0.28$\mu$s 
C) 4.6 $\mu$s 
D) 14$\mu$s 
E) none of these

Question 13

A basic postulate of Einstein's theory of relativity is:

Accepted Answer

A) moving clocks run more slowly than when they are at rest 
B) moving rods are shorter than when they are at rest 
C) light has both wave and particle properties 
D) the laws of physics must be the same for observers moving with uniform velocity relative to each other 
E) everything is relative 
A) moving clocks run more slowly than when they are at rest 
B) moving rods are shorter than when they are at rest 
C) light has both wave and particle properties 
D) the laws of physics must be the same for observers moving with uniform velocity relative to each other 
E) everything is relative

Question 14

An electron (m = 9.11 * 10-31 kg)has a momentum of 1.3 *10-21 kg .m/s.Its kinetic energy is:

Accepted Answer

A) 6.3* 10-14 J 
B) 8.2 *10-14 J 
C) 1.5 *10-13 J 
D) 3.2 *10-13 J 
E) 4.0 *10-13 J 
A) 6.3* 10-14 J 
B) 8.2 *10-14 J 
C) 1.5 *10-13 J 
D) 3.2 *10-13 J 
E) 4.0 *10-13 J

Question 15

Which statement is correct?

Accepted Answer

A) Galilean transformations are correct at any relative speed, but Lorentz transformations are only approximately correct for relative speeds near the speed of light. 
B) Lorentz transformations are correct at any relative speed, but Galilean transformations are only approximately correct for relative speeds near the speed of light. 
C) Galilean transformations are correct at any relative speed, but Lorentz transformations are only approximately correct for relative speeds that are small compared to the speed of light. 
D) Lorentz transformations are correct at any relative speed, but Galilean transformations are only approximately correct for relative speeds that are small compared to the speed of light. 
E) Galilean transformations are only approximately correct for relative speeds that are small compared to the speed of light, and Lorentz transformations are only approximately correct for relative speeds near the speed of light. 
A) Galilean transformations are correct at any relative speed, but Lorentz transformations are only approximately correct for relative speeds near the speed of light. 
B) Lorentz transformations are correct at any relative speed, but Galilean transformations are only approximately correct for relative speeds near the speed of light. 
C) Galilean transformations are correct at any relative speed, but Lorentz transformations are only approximately correct for relative speeds that are small compared to the speed of light. 
D) Lorentz transformations are correct at any relative speed, but Galilean transformations are only approximately correct for relative speeds that are small compared to the speed of light. 
E) Galilean transformations are only approximately correct for relative speeds that are small compared to the speed of light, and Lorentz transformations are only approximately correct for relative speeds near the speed of light.

Question 16

A consequence of Einstein's theory of relativity is:

Accepted Answer

A) moving clocks appear to run more slowly than when they are at rest 
B) moving rods appear longer than when they are at rest 
C) light has both wave and particle properties 
D) the laws of physics must appear the same to all observers moving with uniform velocity relative to each other 
E) everything is relative 
A) moving clocks appear to run more slowly than when they are at rest 
B) moving rods appear longer than when they are at rest 
C) light has both wave and particle properties 
D) the laws of physics must appear the same to all observers moving with uniform velocity relative to each other 
E) everything is relative

Question 17

An event occurs at x = 500 m, t = 0.90 $\mu$s in one frame of reference.Another frame is moving at 0.90c in the negative x direction.The origins coincide at t = 0 and clocks in the second frame are zeroed when the origins coincide.The coordinate and time of the event in the second frame is:

Accepted Answer

A) 500 m, 0.90 $\mu$s 
B) 1700 m, 5.5 $\mu$s 
C) 740 m, 2.4$\mu$s 
D) 260 m, -0.60 $\mu$s 
E) 590 m, -1.4 $\mu$s 
A) 500 m, 0.90 $\mu$s 
B) 1700 m, 5.5 $\mu$s 
C) 740 m, 2.4$\mu$s 
D) 260 m, -0.60 $\mu$s 
E) 590 m, -1.4 $\mu$s

Question 18

Star S1 is moving away from us at a speed of 0.8c.Star S2 is moving away from us in the opposite direction at a speed of 0.5c.The speed of S1 as measured by an observer on S2 is:

Accepted Answer

A) 0.21c 
B) 0.50c 
C) 0.93c 
D) 1.3c 
E) 2.2c 
A) 0.21c 
B) 0.50c 
C) 0.93c 
D) 1.3c 
E) 2.2c

Question 19

Visible light, with a frequency of 6.0 *1014 Hz, is reflected from a spaceship moving directly away at a speed of 0.90c.The frequency of the reflected waves observed at the source is:

Accepted Answer

A) 3.2 *1013 Hz 
B) 1.4 * 1014 Hz 
C) 6.0*1014 Hz 
D) 2.6 * 1015 Hz 
E) 1.1 *1016 Hz 
A) 3.2 *1013 Hz 
B) 1.4 * 1014 Hz 
C) 6.0*1014 Hz 
D) 2.6 * 1015 Hz 
E) 1.1 *1016 Hz

Question 20

The proper time between two events is measured by clocks at rest in a reference frame in which the two events:

Accepted Answer

A) occur at the same time 
B) occur at the same coordinates 
C) are separated by the distance a light signal can travel during the time interval 
D) occur on the Earth's surface 
E) none of the above 
A) occur at the same time 
B) occur at the same coordinates 
C) are separated by the distance a light signal can travel during the time interval 
D) occur on the Earth's surface 
E) none of the above

Exam 37: Relativity

A consequence of Einstein's theory of relativity is:

Two electrons move in opposite directions at 0.70c as measured in the laboratory.The speed of one electron as measured from the other is:

A millionairess was told in 1992 that she had exactly 15 years to live.However, if she immediately takes off, travels away from the Earth at 0.8 c and then returns at the same speed, the last New Year's Day the doctors expect her to celebrate is:

According to the theory of relativity:

A certain particle has a kinetic energy of 3.2 *10-10 J and a momentum of 1.7 * 10-18 kg. m/s.Its mass is:

While emitting light of proper frequency f0, a source moves to the right with speed c/4 relative to reference frame S.A detector, to the left of the source, measures the frequency to be f, which is greater than f0.This means:

Two events occur simultaneously on the x axis of reference frame S, one at x = -a and the other at x = +a.According to an observer moving in the positive x direction:

The magnitude of the momentum of a particle can never exceed:

The velocity of an electron is changed from c/2 in the -x direction to c/2 in the +x direction.As a result, its kinetic energy changes by:

Light from a stationary spaceship is observed, then the spaceship moves directly away from the observer at high speed.As a result, the light seen by the observer has:

A meson when at rest decays 2 μ\muμ s after it is created.If moving in the laboratory at 0.99c, its lifetime according to laboratory clocks would be:

A basic postulate of Einstein's theory of relativity is:

An electron (m = 9.11 * 10-31 kg)has a momentum of 1.3 *10-21 kg .m/s.Its kinetic energy is:

Which statement is correct?

A consequence of Einstein's theory of relativity is:

An event occurs at x = 500 m, t = 0.90 μ\muμ s in one frame of reference.Another frame is moving at 0.90c in the negative x direction.The origins coincide at t = 0 and clocks in the second frame are zeroed when the origins coincide.The coordinate and time of the event in the second frame is:

Star S1 is moving away from us at a speed of 0.8c.Star S2 is moving away from us in the opposite direction at a speed of 0.5c.The speed of S1 as measured by an observer on S2 is:

Visible light, with a frequency of 6.0 *1014 Hz, is reflected from a spaceship moving directly away at a speed of 0.90c.The frequency of the reflected waves observed at the source is:

The proper time between two events is measured by clocks at rest in a reference frame in which the two events:

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A certain particle has a kinetic energy of 3.2 10^-10 J and a momentum of 1.7 10^-18 kg. m/s.Its mass is:

While emitting light of proper frequency f₀, a source moves to the right with speed c/4 relative to reference frame S.A detector, to the left of the source, measures the frequency to be f, which is greater than f₀.This means:

A meson when at rest decays 2 $\mu$ s after it is created.If moving in the laboratory at 0.99c, its lifetime according to laboratory clocks would be:

An electron (m = 9.11 * 10^-31 kg)has a momentum of 1.3 *10^-²¹ kg .m/s.Its kinetic energy is:

An event occurs at x = 500 m, t = 0.90 $\mu$ s in one frame of reference.Another frame is moving at 0.90c in the negative x direction.The origins coincide at t = 0 and clocks in the second frame are zeroed when the origins coincide.The coordinate and time of the event in the second frame is:

Visible light, with a frequency of 6.0 *10¹⁴ Hz, is reflected from a spaceship moving directly away at a speed of 0.90c.The frequency of the reflected waves observed at the source is: