Question 1

A lightning strike is observed before its thunder is heard. Given that the speed of light is $$3.00 	imes 10^8$ m/s and the speed of sound is 340 m/s, which statement best explains this phenomenon?

Accepted Answer

Light travels much faster than sound, so it reaches the observer almost instantaneously compared to sound.

Question 2

Which of the following correctly describes the relationship between wavelength ($$\lambda) $$and frequency ($$
u) $$for electromagnetic waves?

Accepted Answer

They are inversely proportional: as wavelength increases, frequency decreases.

Question 3

A radio station broadcasts at a frequency of $$101$$ MHz. What is the wavelength of this radio wave? (Speed of light $$c = 3.00 	imes 10^8$ m/s)

Accepted Answer

$$2.97 m$$

Question 4

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

Accepted Answer

Gamma rays

Question 5

What is the energy of a photon with a wavelength of $$5.00 	imes 10$$^{-7}$$ m? (Planck's constant h = 6.626$$ 	imes $$10^{-34} J$$·s, $$c = 3.00 	imes 10^8$ m/s)

Accepted Answer

$$3.98 	imes 10$$^{-19}$$ J

Question 6

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Angular momentum quantum number ($$l)$$

Question 7

Which of the following sets of quantum numbers is NOT allowed?

Accepted Answer

$$n=1,\ l=0,\ m_l=-1$$

Question 8

When an electron in a hydrogen atom transitions from $$n=3 to$$ $$n=2$$, what happens?

Accepted Answer

The atom emits a photon and the electron moves to a lower energy level.

Question 9

Which of the following best describes the difference between constructive and destructive interference?

Accepted Answer

Constructive interference occurs when waves add together to make a larger wave; destructive interference occurs when waves cancel each other out.

Question 10

A photon of ultraviolet light has a shorter wavelength than a photon of red light. Which statement is true?

Accepted Answer

The ultraviolet photon has more energy than the red photon.

Question 11

Which of the following transitions in a hydrogen atom would emit radiation with the longest wavelength?

Accepted Answer

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

Question 12

Which of the following best describes the shape of a $$p$$ orbital?

Accepted Answer

Dumbbell-shaped (two lobes)

Question 13

Which phenomenon demonstrates the wave nature of electrons?

Accepted Answer

Diffraction

Question 14

If the energy of an electron in a hydrogen atom is given by $$E_n = -2.18 	imes 10$$^{-18}$$ \frac{1}{n^2$} J$$, what is the energy difference when an electron moves from $$n=4 to$$ $$n=2$$?

Accepted Answer

$$4.09 	imes 10$$^{-19}$$ J

Question 15

Which of the following statements about the electromagnetic spectrum is correct?

Accepted Answer

Gamma rays have the shortest wavelength and highest energy.

Question 16

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

Accepted Answer

Magnetic quantum number ($$m_l)$$

Question 17

A hydrogen atom emits a photon as its electron transitions from $$n=3 to$$ $$n=1. $$Which of the following is true about the energy and wavelength of the emitted photon?

Accepted Answer

The photon has high energy and short wavelength.

The Quantum–Mechanical Model of the Atom: Light, Electromagnetic Radiation, and Atomic Structure

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