Q: A photon of light has a wavelength of $$486 \ \mathrm{nm}. $$What is the energy of this photon? (Use $$h = 6.626 \times 10$$^{-34}$$ \ \mathrm{J \cdot s}$$ and $$c = 2.998 \times 10^8$ \ \mathrm{m/s})$$

$$4.09 \times 10$$^{-19}$$ \ \mathrm{J}$$

Q: The energy difference between two levels in a hydrogen atom is $$2.18 \times 10$$^{-18}$$ \ \mathrm{J}. $$What is the wavelength of the photon emitted during this transition? (Use $$h = 6.626 \times 10$$^{-34}$$ \ \mathrm{J \cdot s}$$ and $$c = 2.998 \times 10^8$ \ \mathrm{m/s})$$

$$9.11 \times 10$$^{-8}$$ \ \mathrm{m}$$

Q: If the speed of light is $$3.00 \times 10^8$ \ \mathrm{m/s}$$, what is the frequency of light with a wavelength of $$600 \ \mathrm{nm}$$?

$$5.00 \times 10$$^{14}$$ \ \mathrm{Hz}$$

Question 1

Which equation correctly relates the speed of light ($$c$$), wavelength ($$\lambda$$), and frequency ($$
u) of $$electromagnetic radiation?

Accepted Answer

$$c = \lambda 
u$$

Question 2

A photon of light has a wavelength of $$486 \ \mathrm{nm}. $$What is the energy of this photon? (Use $$h = 6.626 	imes 10$$^{-34}$$ \ \mathrm{J \cdot s}$$ and $$c = 2.998 	imes 10^8$ \ \mathrm{m/s})$$

Accepted Answer

$$4.09 	imes 10$$^{-19}$$ \ \mathrm{J}$$

Question 3

What does the observation of discrete lines in the emission spectrum of hydrogen suggest about the structure of electrons in the atom?

Accepted Answer

Electrons occupy specific, quantized energy levels.

Question 4

Which of the following transitions in the hydrogen atom would emit light in the visible region of the spectrum according to the Bohr model?

Accepted Answer

$$n = 3 \rightarrow n = 2$$

Question 5

A student observes that the emission spectrum of helium has more lines than that of hydrogen. What is the best explanation for this observation?

Accepted Answer

Helium has more electrons, leading to more possible electronic transitions.

Question 6

Which of the following best describes a continuous spectrum?

Accepted Answer

A spectrum that contains all wavelengths of visible light without interruption.

Question 7

The energy difference between two levels in a hydrogen atom is $$2.18 	imes 10$$^{-18}$$ \ \mathrm{J}. $$What is the wavelength of the photon emitted during this transition? (Use $$h = 6.626 	imes 10$$^{-34}$$ \ \mathrm{J \cdot s}$$ and $$c = 2.998 	imes 10^8$ \ \mathrm{m/s})$$

Accepted Answer

$$9.11 	imes 10$$^{-8}$$ \ \mathrm{m}$$

Question 8

Which of the following statements about the Bohr model of the atom is correct?

Accepted Answer

Electrons can only occupy certain allowed orbits with fixed energies.

Question 9

A hydrogen atom undergoes a transition from $$n = 5 to$$ $$n = 2. $$Which type of electromagnetic radiation is most likely emitted?

Accepted Answer

Visible light

Question 10

If the speed of light is $$3.00 	imes 10^8$ \ \mathrm{m/s}$$, what is the frequency of light with a wavelength of $$600 \ \mathrm{nm}$$?

Accepted Answer

$$5.00 	imes 10$$^{14}$$ \ \mathrm{Hz}$$

Question 11

Which of the following best explains why no visible light is observed in the yellow region of the hydrogen emission spectrum?

Accepted Answer

There are no allowed electronic transitions in hydrogen that emit photons with energies corresponding to yellow light.

Question 12

A sodium street lamp emits light at a wavelength of $$589 \ \mathrm{nm}. $$What is the color of this light, and what does this tell you about the energy of the photons compared to blue light?

Accepted Answer

Yellow; the photons have less energy than blue light photons.

Question 13

Which transition in the hydrogen atom would emit a photon in the ultraviolet region?

Accepted Answer

$$n = 2 \rightarrow n = 1$$

Question 14

The energy of a photon is given by $$E = h 
u. If $$the frequency of a photon is doubled, what happens to its energy?

Accepted Answer

The energy is doubled.

Question 15

A student uses a diffraction grating to analyze the light from a gas discharge tube and observes several bright lines. What does each line represent?

Accepted Answer

A photon emitted as an electron transitions between two energy levels.

Question 16

Which of the following is a real-world application of emission spectra analysis?

Accepted Answer

Identifying elements in distant stars using their spectral lines.

Question 17

According to the Bohr model, what must be true of the change in energy of the electron that is responsible for the emission of light?

Accepted Answer

The electron must move from a higher to a lower energy level, releasing energy as a photon.

Question 18

The Earth is approximately $$93$$ million miles from the Sun. How long does it take light to travel from the Sun to the Earth? (1 mile = $$1.6092 km$$, $$c = 3.00 	imes 10^8$ \ \mathrm{m/s})$$

Accepted Answer

About 8.3 minutes

Question 19

Which of the following best explains why the Bohr model was able to predict the emission spectrum of hydrogen but not of more complex atoms?

Accepted Answer

Hydrogen has only one electron, so electron-electron interactions do not complicate its spectrum.

Atomic Structure, Light Properties, and Emission Spectra: Study Notes

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