Q: A 100-watt light bulb emits light at a wavelength of 525 nm. How many photons are emitted per second? ($$h = 6.626 \times 10$$^{-34}$$ J·s, c = 3.00$$ \times $$10^8 m/s)$$

$$2.64 \times 10$$^{20}$$ photons/s

Question 1

Which of the following statements best describes the wave–particle duality of the electron as revealed by quantum mechanics?

Accepted Answer

Electrons exhibit both particle-like and wave-like properties depending on the experimental conditions.

Question 2

A green laser emits light with a wavelength of 515 nm. What is the frequency of this light? (Speed of light $$c = 3.00 	imes 10^8$ m/s)

Accepted Answer

$$5.82 	imes 10$$^{14}$$ Hz

Question 3

Which of the following types of electromagnetic radiation has the highest energy per photon?

Accepted Answer

Gamma ray

Question 4

According to the photoelectric effect, what happens when light of a frequency below the threshold frequency shines on a metal surface?

Accepted Answer

No electrons are emitted, regardless of the light's intensity.

Question 5

Calculate the energy of a single photon of blue light with a wavelength of 450 nm. ($$h = 6.626 	imes 10$$^{-34}$$ J·s, c = 3.00$$ 	imes $$10^8 m/s)$$

Accepted Answer

$$4.42 	imes 10$$^{-19}$$ J

Question 6

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Angular momentum quantum number ($$l)$$

Question 7

How many orbitals are present in the $$n = 3$$ principal energy level?

Accepted Answer

9

Question 8

Which transition in a hydrogen atom emits light with the shortest wavelength?

Accepted Answer

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

Question 9

A 100-watt light bulb emits light at a wavelength of 525 nm. How many photons are emitted per second? ($$h = 6.626 	imes 10$$^{-34}$$ J·s, c = 3.00$$ 	imes $$10^8 m/s)$$

Accepted Answer

$$2.64 	imes 10$$^{20}$$ photons/s

Question 10

Which statement best summarizes Heisenberg’s uncertainty principle?

Accepted Answer

Either the position or the velocity of an electron can be accurately known at the same instant.

Question 11

Which of the following best explains why we do not observe wave properties for a baseball thrown at a ballpark?

Accepted Answer

Because of the baseball’s large mass, its de Broglie wavelength is minuscule and insignificant compared to the baseball’s size.

Question 12

Which set of quantum numbers is not allowed for an electron in an atom?

Accepted Answer

$$n = 2,\ l = 2,\ m_l = 0,\ m_s = +\frac{1}{2}$$

Question 13

What is the total number of orbitals in the $$n = 4$$ principal energy level?

Accepted Answer

16

Question 14

Which of the following best describes the difference between amplitude and wavelength of a light wave?

Accepted Answer

Amplitude determines the brightness, and wavelength determines the color.

Question 15

Which quantum number(s) determine the orientation of an orbital in space?

Accepted Answer

Magnetic quantum number ($$m_l)$$

Question 16

Which of the following transitions in a hydrogen atom would result in the emission of a photon in the visible region of the electromagnetic spectrum?

Accepted Answer

$$n = 4 \rightarrow n = 2$$

Question 17

Which of the following is a correct statement about the emission spectrum of hydrogen?

Accepted Answer

It consists of a few discrete lines, each corresponding to a specific electron transition.

Question 18

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

Accepted Answer

Energy is inversely proportional to wavelength.

Question 19

Which of the following best describes the meaning of a node in an atomic orbital?

Accepted Answer

A region where the probability of finding an electron is zero.

The Quantum-Mechanical Model of the Atom: Structure, Light, and Electron Behavior

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