Deck 27: Early Quantum Physics and the Photon

Question 1

An $\mathrm{x}$ -ray photon of energy $3.20 \times 10$ -15 J has what wavelength?

A) $200 \mathrm{~nm}$
B) $1.07 \mathrm{~nm}$
C) $32.7 \mathrm{~nm}$
D) $5.73 \mathrm{pm}$
E) $62.1 \mathrm{pm}$

Answer 1

$62.1 \mathrm{pm}$

Question 2

A photon of frequency $6.40 \times 1014 \mathrm{~Hz}$ has what energy?

A) $2.65 \mathrm{eV}$
B) $3.17 \mathrm{eV}$
C) $1.93 \mathrm{eV}$
D) $1.26 \mathrm{eV}$
E) $2.11 \mathrm{eV}$

Answer 2

$2.65 \mathrm{eV}$

Question 3

A $1.00 \mathrm{~mW}$ laser produces photons of wavelength $633 \mathrm{~nm}$ . How many photons per second does the laser emit?

A) $1.58 \times 10^{3}$
B) $6.24 \times 1015$
C) $3.19 \times 10^{15}$
D) $1.60 \times 1019$
E) $1.06 \times 1010$

Answer 3

$3.19 \times 10^{15}$

Question 4

The work function of a surface is $6.53 \times 10^{-19} \mathrm{~J}$ . What is this quantity in $\mathrm{eV}$ ?

A) 3.13
B) 4.70
C) 2.46
D) 4.08
E) 3.93

Question 5

Photons of energy $4.20 \mathrm{eV}$ bombard a surface, which emits photoelectrons with kinetic energies from 0 to $1.80 \mathrm{eV}$ . What is the threshold frequency for this surface?

A) $1.35 \times 1014 \mathrm{~Hz}$
B) $5.80 \times 10^{14} \mathrm{~Hz}$
C) $7.74 \times 1015 \mathrm{~Hz}$
D) $7.74 \times 1014 \mathrm{~Hz}$
E) $1.35 \times 10^{15} \mathrm{~Hz}$

Question 6

An x-ray tube produces photons with wavelengths down to a minimum of $0.0827 \mathrm{~nm}$ . What is the accelerating potential for this tube?

A) $9.22 \mathrm{kV}$
B) $15.0 \mathrm{kV}$
C) $10.0 \mathrm{kV}$
D) $123 \mathrm{kV}$
E) $8.00 \mathrm{kV}$

Question 7

An $x$ -ray photon with wavelength $15.0 \mathrm{pm}$ is scattered at $84.0^{\circ}$ by an electron. What is the wavelength of the scattered photon?

A) $31.0 \mathrm{pm}$
B) $12.8 \mathrm{pm}$
C) $14.9 \mathrm{pm}$
D) $1.57 \mathrm{pm}$
E) $17.2 \mathrm{pm}$

Question 8

An $x$ -ray photon with wavelength $15.0 \mathrm{pm}$ is scattered through $84.0^{\circ}$ by an electron. What is the resulting kinetic energy of the electron?

A) $10.5 \mathrm{keV}$
B) $59.5 \mathrm{keV}$
C) $15.0 \mathrm{keV}$
D) $568 \mathrm{keV}$
E) $30.1 \mathrm{keV}$

Question 9

In a Compton scattering experiment, the scattered photon has a wavelength of $6.55 \mathrm{pm}$ . If the scattering angle is $50^{\circ}$ , what was the wavelength of the incident photon?

A) $0.868 \mathrm{pm}$
B) $7.42 \mathrm{pm}$
C) $3.28 \mathrm{pm}$
D) $5.68 \mathrm{pm}$
E) $2.43 \mathrm{pm}$

Question 10

The mathematician Johann Jakob Balmer found that the formula $1 / \lambda=\mathrm{R}\left(1 / \mathrm{n}_{\mathrm{f}}^{2}-1 / \mathrm{n}_{\mathrm{i}}^{2}\right)$ works for the hydrogen emission lines in the visible range, with what value of $n_{\mathrm{f}}$ ?

A) 1
B) 2
C) 3
D) 4
E) 5

Question 11

According to the Bohr model, what is the potential energy of an electron in the ground state of the hydrogen atom?

A) $-27.2 \mathrm{eV}$
B) $27.2 \mathrm{eV}$
C) $-13.6 \mathrm{eV}$
D) 0
E) $13.6 \mathrm{eV}$

Question 12

What is the highest energy of a photon in the Balmer series?

A) $0.94 \mathrm{eV}$
B) $3.40 \mathrm{eV}$
C) $1.89 \mathrm{eV}$
D) $1.51 \mathrm{eV}$
E) $0.66 \mathrm{eV}$

Question 13

For the ion $\mathrm{He}^{+}$ , what is the energy of the ground state?

A) $-13.6 \mathrm{eV}$
B) $-27.2 \mathrm{eV}$
C) $-3.40 \mathrm{eV}$
D) $-6.80 \mathrm{eV}$
E) $-54.4 \mathrm{eV}$

Question 14

What is the radius of the ground state of $\mathrm{He}^{+}$ ?

A) $0.0529 \mathrm{~nm}$
B) $0.212 \mathrm{~nm}$
C) $0.193 \mathrm{~nm}$
D) $0.0265 \mathrm{~nm}$
E) $0.106 \mathrm{~nm}$

Question 15

According to the Bohr model, what is the kinetic energy of an electron in the ground state of hydrogen?

A) $6.80 \mathrm{eV}$
B) $27.2 \mathrm{eV}$
C) 0
D) $1.88 \mathrm{eV}$
E) $13.6 \mathrm{eV}$

Question 16

What is the smallest energy photon that a hydrogen atom in the ground state can absorb?

A) $3.40 \mathrm{eV}$
B) any energy
C) $1.90 \mathrm{eV}$
D) $13.6 \mathrm{eV}$
E) $10.2 \mathrm{eV}$

Question 17

If a hydrogen atom in the ground state absorbs a $20.0 \mathrm{eV}$ photon, what kinetic energy of the electron results?

A) $33.6 \mathrm{eV}$
B) this cannot happen
C) $13.6 \mathrm{eV}$
D) $6.4 \mathrm{eV}$
E) $20.0 \mathrm{eV}$

Question 18

What is the maximum wavelength photon that can produce a pair of tau particles (mass $1.777 \mathrm{GeV} / \mathrm{c}^{2}$ ) by pair production?

A) $6.98 \times 10^{-7} \mathrm{~nm}$
B) $1.74 \times 10^{-7} \mathrm{~nm}$
C) $8.72 \times 10^{-8} \mathrm{~nm}$
D) $3.49 \times 10^{-7} \mathrm{~nm}$