ET 4 Practice

What is the correct order of increasing energy?

• Microwaves, visible light, ultraviolet light, x-rays, γ-rays

• Microwaves, x-rays, γ-rays, visible light, ultraviolet light

• Microwaves, ultraviolet light, visible light, x-rays, γ-rays

• X-rays, γ-rays, microwaves, visible light, ultraviolet light

Answer explanation

The correct order of increasing energy (E) is based on the electromagnetic spectrum. Microwaves have the lowest energy, followed by visible light, ultraviolet light, x-rays, and finally γ-rays, which have the highest energy.

What is the correct order of increasing wavelength?

• γ-rays, UV, X-rays, radio, infrared

• γ-rays, X-rays, UV, infrared, radio

• X-rays, microwaves, visible light, γ-rays, ultraviolet light

• X-rays, γ-rays, microwaves, visible light, ultraviolet light

Answer explanation

The correct order of increasing wavelength (λ) is based on the electromagnetic spectrum.

γ-rays have the shortest wavelength (λ), followed by X-rays, UV, infrared (IR), and radio waves with the longest wavelength.

What is the correct order of increasing velocity (v)?

• Microwaves, visible light, ultraviolet light, x-rays, γ-rays

• Microwaves, x-rays, γ-rays, visible light, ultraviolet light

• Microwaves, ultraviolet light, visible light, x-rays, γ-rays

• X-rays, γ-rays, microwaves, visible light, ultraviolet light

Answer explanation

The correct order of increasing velocity (v) is based on the electromagnetic spectrum. Microwaves have the lowest velocity, followed by visible light, ultraviolet light, x-rays, and finally γ-rays, which have the highest velocity.

If a photon’s wavelength is 663 nm, what is its energy?

• 4.40 x 10^-37 J

• 3.00 x 10^-22 J

• 4.40 x 10^-40 J

• 3.00 x 10^-19 J

Answer explanation

The energy of a photon can be calculated using the formula E = hc/λ. Here, h = 6.626 x 10^-34 J·s, c = 3.00 x 10⁸ m/s, and λ = 663 nm (or 663 x 10^-9 m). This gives E ≈ 3.00 x 10^-19 J, which is the correct answer.

Remember, both the speed of light (c = 3.00 x 10⁸ m/s) and Planck's constant (h = 6.626 x 10^-34 J·s) are provided on the Constants section of your Formula Chart. Also, notice that Dr. Laude made sure that the numeric value for wave length cancels out with Plank's Constant, meaning you know your answer must be 3.00 x 10^? . Then it is just dividing exponents, which is addition and subtraction, to get you to your answer.

If a photon’s wavelength is 1328 nm, what is its energy?

• 2.20 x 10^-22 J

• 1.50 x 10^-22 J

• 2.20 x 10^-19 J

• 1.50 x 10^-19 J

Answer explanation

The energy of a photon can be calculated using the formula E = hc/λ. Here, h = 6.626 x 10^-34 J·s, c = 3.00 x 10⁸ m/s, and λ = 1328 nm (or 1328 x 10^-9 m). This gives E ≈ 1.50 x 10^-19 J, which is the correct answer.

Remember, both the speed of light (c = 3.00 x 10⁸ m/s) and Planck's constant (h = 6.626 x 10^-34 J·s) are provided on the Constants section of your Formula Chart. Also, notice that Dr. Laude made sure that the numeric value for wave length double Plank's Constant, meaning you know your answer must be 1.50 x 10^? . Then it is just dividing exponents, which is addition and subtraction, to get you to your answer.

If a photon’s wavelength is 332 nm, what is its energy?

• 5.20 x 10^-22 J

• 6.00 x 10^-22 J

• 5.20 x 10^-19 J

• 6.00 x 10^-19 J

Answer explanation

The energy of a photon can be calculated using the formula E = hc/λ. Here, h = 6.626 x 10^-34 J·s, c = 3.00 x 10⁸ m/s, and λ = 332 nm (or 332 x 10^-9 m). This gives E ≈ 6.00 x 10^-19 J, which is the correct answer.

Remember, both the speed of light (c = 3.00 x 10⁸ m/s) and Planck's constant (h = 6.626 x 10^-34 J·s) are provided on the Constants section of your Formula Chart. Also, notice that Dr. Laude made sure that the numeric value for wave length half of Plank's Constant, meaning you know your answer must be 6.00 x 10^? . Then it is just dividing exponents, which is addition and subtraction, to get you to your answer.

When a given molecule absorbs a photon of infrared (IR) radiation

• It promotes electrons intro delocalized bonding orbitals.

• It begins to vibrate.

• It begins to rotate.

• Its electrons are excited to higher energy levels.

Answer explanation

When a molecule absorbs infrared radiation, it primarily causes the bonds within the molecule to vibrate. This is the key interaction with IR radiation, making 'It begins to vibrate' the correct answer.

Radiofrequency radiation has what kind of impact on matter?

• It makes the nuclei spin

• It makes the electrons spin

• It makes the molecule rotate

• It makes the nucleus split

Answer explanation

Radiofrequency radiation primarily affects the nuclei of atoms, causing them to spin. This is the basis for techniques like nuclear magnetic resonance (NMR), which utilize the spin of nuclei in a magnetic field.

Microwaves have what kind of impact on matter?

• It makes the nuclei spin

• It makes the electrons spin

• It makes the molecule rotate

• It makes the nucleus split

Answer explanation

Remember, microwaves cause BOTH the electrons to spin AND cause molecules to rotate. In the case of water (H₂O), this creates kinetic energy, causing food to heat.

What happens to molecules that absorb infrared (IR) energy?

• Causes skin to burn

• Causes the nucleus to fall apart

• Causes molecules to vibrate

• Causes the electrons to rotate