Question 1

A metal surface is irradiated with light of wavelength 400 nm, causing electrons to be ejected with a maximum velocity of $$6.22 	imes 10^5$ m/s. What is the work function $$\phi$$ of the metal in joules? (Use h = 6.626$$ 	imes $$10^{-34} J$$·s, $$c = 3.00 	imes 10^8$ m/s, m_e = 9.11$$ 	imes $$10^{-31} kg)$$

Accepted Answer

$$3.10 	imes 10$$^{-19}$$ J

Question 2

A red laser pointer emits light at a wavelength of 650 nm. What is the energy of a single photon emitted by this laser? (Use $$h = 6.626 	imes 10$$^{-34}$$ J·s, c = 3.00$$ 	imes $$10^8 m/s)$$

Accepted Answer

$$2.04 	imes 10$$^{-19}$$ J

Question 3

Which of the following best describes the work function $$\phi in $$the context of the photoelectric effect?

Accepted Answer

The amount of energy required to remove an electron from a metal surface

Question 4

According to the Bohr model, what is the energy (in J) of an electron in the $$n=3$$ orbit of a hydrogen atom? (Use $$E_n = \left(-2.178 	imes 10$$^{-18}$$ight) \dfrac{Z^2$}{n^2$}$$, $$Z=1$$ for hydrogen)

Accepted Answer

$$-6.05 	imes 10$$^{-19}$$ J

Question 5

A hydrogen atom undergoes a transition from $$n=5 to$$ $$n=2. $$What is the energy change per atom (in J)? (Use $$E_n = \left(-2.178 	imes 10$$^{-18}$$ight) \dfrac{1}{n^2$})$$

Accepted Answer

$$-4.58 	imes 10$$^{-19}$$ J

Question 6

Which series in the hydrogen emission spectrum corresponds to transitions ending at $$n=1$$ and in which region of the electromagnetic spectrum does it lie?

Accepted Answer

Lyman series, ultraviolet region

Question 7

If a photon is being emitted by a hydrogen atom, what is the sign of $$\Delta E$$ and what does this indicate about the electron's movement?

Accepted Answer

$$\Delta E is $$negative; electron moves to a lower energy level

Question 8

Which equation correctly relates the kinetic energy of an ejected electron to the energy of the incident photon and the work function?

Accepted Answer

$$KE = h
u - \phi$$

Question 9

A photon with a wavelength of 30.4 nm is shone on platinum, and electrons are ejected with a kinetic energy of $$5.522 	imes 10$$^{-18}$$ J. What is the work function $$\phi$$ for platinum? (Use h = 6.626$$ 	imes $$10^{-34} J$$·s, $$c = 3.00 	imes 10^8$ m/s)

Accepted Answer

$$6.53 	imes 10$$^{-18}$$ J

Question 10

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

Accepted Answer

Electrons in an atom can only occupy certain orbits at fixed distances from the nucleus

Question 11

The Rydberg formula for the hydrogen spectrum is $$\dfrac{1}{\lambda} = R_H \left( \dfrac{1}{n_1$^2} - \dfrac{1}{n_2$^2} \right). $$What does $$n_1$$ represent?

Accepted Answer

The final energy level of the electron

Question 12

Which of the following transitions in a hydrogen atom would result in the emission of the highest energy photon?

Accepted Answer

$$n=2 to$$ $$n=1$$

Question 13

If the emission spectrum of hydrogen contains a line at $$\lambda = 2620 nm in $$the Brackett series, what is the value of $$n_{final}$$ for this transition?

Accepted Answer

$$n_{final} = 4$$

Question 14

Which of the following best explains why hydrogen exhibits a line spectrum rather than a continuous spectrum?

Accepted Answer

Electrons in hydrogen can only occupy specific, quantized energy levels

Question 15

What is the frequency (Hz) of light emitted when a hydrogen atom transitions from $$n=5 to$$ $$n=2$$? (Use $$\Delta E = h
u$$, $$\Delta E = -4.58 	imes 10$$^{-19}$$ J, h = 6.626$$ 	imes $$10^{-34} J$$·s)

Accepted Answer

$$6.91 	imes 10$$^{14}$$ Hz

The Nature of Light and Atomic Spectroscopy: Study Notes

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