Answers3262 CR Physics B 2526Unit Test

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What are some applications of the field of spectroscopy? Select 5 options. for identifying elements in a samplefor determining the distance and velocity of galaxiesfor producing neon lightsfor determining types of chemical bondsfor use in medical imaging devicesfor killing bacteria in foods

A
for identifying elements in a sample
B
for determining the distance and velocity of galaxies
C
for producing neon lights
D
for determining types of chemical bonds
E
for use in medical imaging devices
F
for killing bacteria in foods
2
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Which best describes the present-day universe?

A
opaque, expanding very slowly, stars produce heavy elements
B
transparent, expanding at an accelerated rate, stars produce heavy elements
C
opaque, expanding at an accelerated rate, stars produce only hydrogen and helium
D
transparent, expanding very slowly, stars produce only hydrogen and helium
3

What is the study of the spectra produced from the emission and absorption of electromagnetic radiation?

A
study of absorption spectrums
B
study of emission spectrum
C
nanotechnology
D
spectroscopy
4

The emission spectrums are known for the elements below.What elements are in the unknown sample? Select 2 options. boronlithiumhydrogenheliumpotassium

Question illustration
A
boron
B
lithium
C
hydrogen
D
helium
E
potassium
5

What type of spectrum is produced when electromagnetic radiation is emitted or absorbed as electrons change energy levels in an atom? ( Please list one word only and lower case )

Answer not available
6

Clara made a chart to summarize some of the evidence that supports the big bang theory.Which best describes Clara’s error?

Question illustration
A
During redshift, the light source and observer move closer together, not farther apart.
B
The CMB is blue-shifted, not red-shifted, to the microwave region.
C
The temperature of the CMB is cooler, not hotter, than at the time of the big bang.
D
The redshift indicates approaching, not receding, galaxies.
7

Finn drew a diagram to compare Einstein’s two postulates of relativity. Which labels belong in the areas marked X, Y, and Z?

Question illustration
A
X: applies to objects moving almost at the speed of lightY: describes the effect of constant motion in space on timeZ: speed of light is always 3.0 × 108 m/s
B
X: speed of light is always 3.0 × 108 m/s Y: applies to objects moving almost at the speed of lightZ: describes the effect of constant motion in space on time
C
X: speed of light through empty space is the same for all observersY: laws of physics are the same for all uniformly moving frames of motionZ: applies to objects with constant velocity
D
X: laws of physics are the same for all uniformly moving frames of motionY: applies to objects with constant velocityZ: speed of light through empty space is the same for all observers
8

What is luminosity?

A
the amount of energy a star emits in a unit of time
B
the brightness of a star as seen from Earth
C
the average temperature of a star during its life cycle
D
the degree of shift toward the red end of the spectrum
9

A Hertzsprung-Russel diagram is shown.

Question illustration
A
red giants
B
white dwarfs
C
supergiants
D
main sequence
10

The chart shows different speeds at which theoretical spacecraft are traveling horizontally. The speeds are represented as percentages of the speed of light the spacecrafts are traveling, where 0.20c = 6 × 107 m/s.

Question illustration
A
W
B
X
C
Y
D
Z
11

Which describes what an outside observer at rest would observe about a spaceship that speeds up and approaches the speed of light?

A
Time moves faster on the spaceship, and the length of the spaceship decreases.
B
Time moves faster on the spaceship, and the length of the spaceship increases.
C
Time moves more slowly on the spaceship, and the length of the spaceship decreases.
D
Time moves more slowly on the spaceship, and the length of the spaceship increases.
12

According to Einstein’s first postulate about the special theory of relativity, which best explains why a person feels like he or she is sitting still on a train that is moving at a constant speed of 60 miles per hour?

A
The train is moving more slowly than the speed of light.
B
The person is moving at the same speed as the train.
C
The motion of the train and of the person are not relative to each other.
D
The reference frame of the person is inside the train.

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