Q: A laser emits light with a wavelength of $$532\ \mathrm{nm}$$ and a total energy of $$3.85\ \mathrm{mJ}. $$How many photons are in the laser pulse? (Planck's constant $$h = 6.626 \times 10$$^{-34}$$\ \mathrm{J\cdot s}$$, speed of light $$c = 3.00 \times 10^8$\ \mathrm{m/s})$$

$$1.03 \times 10$$^{16}$$ photons

Q: What is the relationship between the wavelength $$(\lambda)$$ and frequency $$(\nu) of $$electromagnetic radiation?

$$\lambda$$ and $$\nu$$ are inversely proportional: $$c = \lambda \nu$$

Q: Calculate the energy of a photon with a wavelength of $$632.8\ \mathrm{nm}$$. ($$h = 6.626 \times 10$$^{-34}$$\ \mathrm{J\cdot s}$$, $$c = 3.00 \times 10^8$\ \mathrm{m/s})$$

$$3.14 \times 10$$^{-19}$$\ \mathrm{J}$$

Q: What is the de Broglie wavelength of an electron traveling at $$1.35 \times 10^6$\ \mathrm{m/s}$$? (mass of electron $$m = 9.11 \times 10$$^{-31}$$\ \mathrm{kg}$$, $$h = 6.626 \times 10$$^{-34}$$\ \mathrm{J\cdot s})$$

$$5.40 \times 10$$^{-10}$$\ \mathrm{m}$$

Question 1

Which statement best describes the wave-particle duality of light?

Accepted Answer

Light exhibits both wave-like and particle-like properties depending on the experiment.

Question 2

A laser emits light with a wavelength of $$532\ \mathrm{nm}$$ and a total energy of $$3.85\ \mathrm{mJ}. $$How many photons are in the laser pulse? (Planck's constant $$h = 6.626 	imes 10$$^{-34}$$\ \mathrm{J\cdot s}$$, speed of light $$c = 3.00 	imes 10^8$\ \mathrm{m/s})$$

Accepted Answer

$$1.03 	imes 10$$^{16}$$ photons

Question 3

Which of the following transitions in a hydrogen atom will produce light with the longest wavelength?

Accepted Answer

From $$n=3 to$$ $$n=2$$

Question 4

What is the relationship between the wavelength $$(\lambda)$$ and frequency $$(
u) of $$electromagnetic radiation?

Accepted Answer

$$\lambda$$ and $$
u$$ are inversely proportional: $$c = \lambda 
u$$

Question 5

Which quantum number determines the shape of an orbital?

Accepted Answer

Angular momentum quantum number $$(\ell)$$

Question 6

Calculate the energy of a photon with a wavelength of $$632.8\ \mathrm{nm}$$. ($$h = 6.626 	imes 10$$^{-34}$$\ \mathrm{J\cdot s}$$, $$c = 3.00 	imes 10^8$\ \mathrm{m/s})$$

Accepted Answer

$$3.14 	imes 10$$^{-19}$$\ \mathrm{J}$$

Question 7

Which statement about the photoelectric effect is correct?

Accepted Answer

Electrons are emitted only if the frequency of light exceeds a threshold value, regardless of intensity.

Question 8

What is the de Broglie wavelength of an electron traveling at $$1.35 	imes 10^6$\ \mathrm{m/s}$$? (mass of electron $$m = 9.11 	imes 10$$^{-31}$$\ \mathrm{kg}$$, $$h = 6.626 	imes 10$$^{-34}$$\ \mathrm{J\cdot s})$$

Accepted Answer

$$5.40 	imes 10$$^{-10}$$\ \mathrm{m}$$

Question 9

Which combination of quantum numbers is NOT allowed for an electron in an atom?

Accepted Answer

$$n=2,\ \ell=2,\ m_\ell=0,\ m_s=+\frac{1}{2}$$

Question 10

Which scientist is credited with proposing the uncertainty principle?

Accepted Answer

Werner Heisenberg

Question 11

What is the minimum frequency required to eject electrons from a metal in the photoelectric effect called?

Accepted Answer

Threshold frequency

Question 12

Which quantum number describes the orientation of an orbital in space?

Accepted Answer

Magnetic quantum number $$(m_\ell)$$

Question 13

If an electron in a hydrogen atom transitions from $$n=5 to$$ $$n=2$$, what type of spectrum is produced?

Accepted Answer

Emission spectrum

Question 14

Which of the following best explains why electrons in atoms have quantized energy levels?

Accepted Answer

Electrons can only exist at certain distances from the nucleus, corresponding to specific energy values.

Question 15

What is the formula for the energy of a photon?

Accepted Answer

$$E = h 
u$$

Question 16

Which quantum number can have values from $$-\ell to$$ $$+\ell$$ including zero?

Accepted Answer

Magnetic quantum number $$(m_\ell)$$

Question 17

Which statement about the radial distribution function for an $$s$$ orbital is correct?

Accepted Answer

The probability of finding an electron is maximum at a certain distance from the nucleus, not at the nucleus.

Question 18

Which scientist proposed that particles such as electrons have wavelike properties?

Accepted Answer

Louis de Broglie

Question 19

What is the effect called when light bends around an obstacle or opening comparable in size to its wavelength?

Accepted Answer

Diffraction

Question 20

Which of the following best describes constructive interference?

Accepted Answer

Two waves are in phase and their amplitudes add together.

Chapter 8: The Quantum-Mechanical Model of the Atom – Study Notes

Study Guide - Practice Questions

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