Chapter 4

Question 1

Wien’s law states that the wavelength of the peak radiation emitted by a blackbody is ________ the temperature of a blackbody.

Answer 1

inversely proportional to

Question 2

Stefan’s law states that the total energy radiated by a blackbody depends on the ________ power of the temperature of the blackbody.

Answer 2

fourth

Question 3

Imagine an emission spectrum produced by a container of hydrogen gas. Changing the amount of hydrogen in the container will change the colors of the lines in the spectrum.

Answer 3

False

Question 4

Imagine an emission spectrum produced by a container of hydrogen gas. Changing the gas in the container from hydrogen to helium will change the colors of the lines occurring in the spectrum.

Answer 4

True

Question 5

An electron moves to a higher energy level in an atom after absorbing a photon of a specific energy.

Answer 5

True

Question 6

A star much cooler than the Sun would appear

Answer 6

red.

Question 7

Astronomers analyze starlight to determine a star’s

Answer 7

1. motion.
2. temperature.
3. composition.

Question 8

According to Figure 2.11 in the textbook (Blackbody Curves), an object having a temperature of 1000 emits mostly

Answer 8

infrared light

Question 9

The effect of a cool, dilute gas between an observer and a continuous hot source is that ________.

Answer 9

dark absorption lines will appear in the spectrum. The cool gas will absorb light from the source only at certain specific wavelengths, producing absorption lines.

Question 10

What kind of spectrum does the Sun have?

Answer 10

An absorption spectrum.

Question 11

Which of the following photons is most energetic?

Answer 11

Gamma-ray

Question 12

In non-ionized hydrogen, for instance, what does a higher orbital state have more of than a lower orbital state?

Answer 12

Energy

Question 13

Which of the following statements does NOT apply to the structure of atoms?

Answer 13

Protons and electrons make up the nucleus. there are no electrons in the nucleus.

Question 14

When an electron goes from a higher energy level back down to the ground state, what is the most accurate way to describe the light it emits?

Answer 14

One or more photons, equal in total energy to the energy the electron absorbed to move up to the higher level. The higher the initial “jump” the more possibilities for the number of photons emitted. However, the total energy must always be the same as the energy originally absorbed.

Question 15

What will happen to the absorption and/or emission spectral lines of an object moving away from Earth at high speed?

Answer 15

They will be shifted toward the red end of the spectrum. Redshift always results when the source and observer are moving away from each other.