Q: Which equation gives the maximum kinetic energy of an emitted photoelectron in the photoelectric effect?

$$ (E_K)_{max} = h \nu - \Phi $$

Q: A metal has a work function $$ \Phi = 2.0 \text{ eV} . $$What is the minimum frequency of light required to eject electrons from its surface?

$$ \nu_0$ = \dfrac{2.0 \times 1.60 \times 10$$^{-19}$$ \text{ J}}{6.626 \times 10$$^{-34}$$ \text{ J} \cdot \text{s}} $$

Q: If the energy of a photon is $$ 4.0 \times 10$$^{-19}$$ \text{ J} $$ and the work function of the metal is $$ 2.5 \times 10$$^{-19}$$ \text{ J} $$, what is the maximum kinetic energy of the emitted photoelectron?

$$ 1.5 \times 10$$^{-19}$$ \text{ J} $$

Q: A photon of wavelength $$ 500 \text{ nm} $$ strikes a metal surface. What is the energy of this photon?

$$ E = \dfrac{6.626 \times 10$$^{-34}$$ \text{ J} \cdot \text{s} \times 3.00 \times 10^8$ \text{ m/s}}{500 \times 10$$^{-9}$$ \text{ m}} $$

Q: If the threshold frequency for a metal is $$ 5.0 \times 10$$^{14}$$ \text{ Hz} $$, what is the threshold wavelength?

$$ \$$lambda_0$$ = \dfrac{3.00 \times 10^8$ \text{ m/s}}{5.0 \times 10$$^{14}$$ \text{ Hz}} $$

Question 1

Which statement best describes the photoelectric effect?

Accepted Answer

Electrons are emitted from the surface of a metal when light of sufficient frequency strikes it.

Question 2

What is the minimum condition required for the photoelectric effect to occur?

Accepted Answer

The frequency of the incident light must be above a threshold value.

Question 3

Which equation gives the maximum kinetic energy of an emitted photoelectron in the photoelectric effect?

Accepted Answer

$$ (E_K)_{max} = h 
u - \Phi $$

Question 4

A metal has a work function $$ \Phi = 2.0 	ext{ eV} . $$What is the minimum frequency of light required to eject electrons from its surface?

Accepted Answer

$$ 
u_0$ = \dfrac{2.0 	imes 1.60 	imes 10$$^{-19}$$ 	ext{ J}}{6.626 	imes 10$$^{-34}$$ 	ext{ J} \cdot 	ext{s}} $$

Question 5

If the energy of a photon is $$ 4.0 	imes 10$$^{-19}$$ 	ext{ J} $$ and the work function of the metal is $$ 2.5 	imes 10$$^{-19}$$ 	ext{ J} $$, what is the maximum kinetic energy of the emitted photoelectron?

Accepted Answer

$$ 1.5 	imes 10$$^{-19}$$ 	ext{ J} $$

Question 6

Which of the following best explains why increasing the intensity of light below the threshold frequency does NOT cause electron emission?

Accepted Answer

Intensity increases the number of photons, but each photon still lacks the required energy to eject electrons.

Question 7

A photon of wavelength $$ 500 	ext{ nm} $$ strikes a metal surface. What is the energy of this photon?

Accepted Answer

$$ E = \dfrac{6.626 	imes 10$$^{-34}$$ 	ext{ J} \cdot 	ext{s} 	imes 3.00 	imes 10^8$ 	ext{ m/s}}{500 	imes 10$$^{-9}$$ 	ext{ m}} $$

Question 8

Which of the following is a direct experimental observation of the photoelectric effect?

Accepted Answer

Electrons are emitted instantly when light of sufficient frequency strikes the metal.

Question 9

If the threshold frequency for a metal is $$ 5.0 	imes 10$$^{14}$$ 	ext{ Hz} $$, what is the threshold wavelength?

Accepted Answer

$$ \$$lambda_0$$ = \dfrac{3.00 	imes 10^8$ 	ext{ m/s}}{5.0 	imes 10$$^{14}$$ 	ext{ Hz}} $$

Question 10

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

Accepted Answer

Electrons occupy fixed orbits with quantized energies.

Question 11

What is the relationship between the energy of a photon and its frequency?

Accepted Answer

$$ E = h 
u $$

Question 12

Which of the following best describes the difference between a continuous spectrum and an emission spectrum?

Accepted Answer

A continuous spectrum contains all wavelengths, while an emission spectrum contains only specific wavelengths.

Question 13

In a flame test, why do different elements produce different colors?

Accepted Answer

Each element has a unique set of energy levels, resulting in emission of photons with specific energies.

Question 14

Which formula is used to calculate the velocity of an emitted photoelectron with maximum kinetic energy?

Accepted Answer

$$ v_{max} = \sqrt{\dfrac{2(E_{photon} - \Phi)}{m_e}} $$

Question 15

A photon with energy $$ 3.0 	ext{ eV} $$ strikes a metal with work function $$ 2.0 	ext{ eV} . $$What is the speed of the emitted electron? ($$ m_e = 9.11 	imes 10$$^{-31}$$ 	ext{ kg} )$$

Accepted Answer

$$ v = \sqrt{\dfrac{2 	imes 1.0 	imes 1.60 	imes 10$$^{-19}$$ 	ext{ J}}{9.11 	imes 10$$^{-31}$$ 	ext{ kg}}} $$

Question 16

Which of the following is NOT a prediction of classical wave theory for the photoelectric effect?

Accepted Answer

Electrons are emitted only if the light frequency exceeds a threshold value.

Question 17

Which of the following best explains why the photoelectric effect supports the particle nature of light?

Accepted Answer

Electrons are emitted only when individual photons have enough energy, regardless of light intensity.

Photoelectric Effect and Atomic Spectra: Principles and Applications

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