Chapter 2 Section 5: Practice

During a science fair, Ian and Evan were discussing about the electromagnetic spectrum. Ian believes it is a continuum of energies ranging from gamma and X-rays to radio and microwaves. Can you tell if Ian is correct?

• Yes, it is a continuum of energies ranging from gamma and X-rays to radio and microwaves

• No, it is a continuum of energies ranging from visible light to infrared light

• No, it is a continuum of energies ranging from visible light to X-rays

• No, it is a continuum of energies ranging from ultraviolet light to radio waves

Answer explanation

Ian is correct. The electromagnetic spectrum is a continuum of energies ranging from gamma and X-rays to radio and microwaves.

El and Juno are in a music class. They learned about different units of measurement in music. Juno asked, 'El, do you know what is the unit of frequency in music?'

• Newton

• Hertz

• Joule

• Watt

Answer explanation

The unit of frequency in music is Hertz. Hertz measures the number of cycles per second in a sound wave.

Mary and Ben are having a debate. Mary says that light travels at a speed of 3.00 x 10^8 m/s in a vacuum, while Ben believes it's slower. Who is correct?

• Mary with 3.00 x 10^8 m/s

• Ben with 2.50 x 10^8 m/s

• Both are wrong, it's 3.50 x 10^8 m/s

• Both are wrong, it's 2.00 x 10^8 m/s

Answer explanation

Mary is correct. Light travels at a speed of 3.00 x 10^8 m/s in a vacuum.

Dovid, Ben, Phil, Alex, and Juno are working on a science project about the hydrogen spectrum. They need to calculate the wavelength of the hydrogen spectrum. Which equation should they use?

• E = mc²

• c = λƒ

• ΔE = hƒ

• 1/ λ= R_H( 1 n² ₁ - 1 n² ₂ )

Answer explanation

The correct equation to calculate the wavelength of the hydrogen spectrum is 1/ λ= R_H( 1 n^2_1 - 1 n^2_2 ).

During a science experiment, Gabby and Ian were studying the energy emitted by a hydrogen atom. They observed an electron falling from the 3rd level to the 2nd level. What is the energy emitted in this process?

• 3.03 x 10^-19 J

• 1.82 x 10^5 J/mol

• 43.6 kcal/mol

• 182 kJ/mol

Answer explanation

The energy emitted when an electron falls from the 3rd level to the 2nd level of a hydrogen atom is 1.82 x 10^5 J/mol. This is the correct choice.

During a science fair, Richie and El were discussing about the hydrogen spectrum. Richie claimed that the Lyman series lies in the ultraviolet region. El, however, disagreed and suggested other series. Which series did Richie mention that lies in the ultraviolet region?

• Balmer series

• Lyman series

• Paschen series

• Brackett series

Answer explanation

Richie mentioned the Lyman series, which lies in the ultraviolet region. This series consists of transitions to the ground state.

During a science fair, Ian proposed the idea that the single electron of a hydrogen atom in his project could only occupy certain energy levels. Who originally proposed this notion?

• Erwin Schrödinger

• Isaac Newton

• Niels Bohr

• Johann Balmer

Answer explanation

Niels Bohr originally proposed the notion that the single electron of a hydrogen atom can only occupy certain energy levels.

Ben and Katia are studying the Bohr model for their physics class. They learned that there is a specific term for the energy difference between any two adjacent orbits in this model. What is this term called?

• Quantum of energy

• Photon

• Electron volt

• Planck's constant

Answer explanation

The term for the energy difference between adjacent orbits in the Bohr model is called the quantum of energy.

Gabby is studying the behavior of electrons in an atom for her science project. She is particularly interested in the state of an electron when it has the lowest energy. What is this state called?

• Ground state

• Excited state

• Quantum state

• Orbital state

Answer explanation

The state of an electron with the lowest energy is called the ground state. It is the correct choice because electrons tend to occupy the lowest energy level available.

In 1922, Niels Bohr won the Nobel Prize for a significant scientific achievement. If Piper was to write a report on this, which topic should she choose?

• Development of the quantum theory

• Discovery of the electron

• Explanation of the structure of the hydrogen atom and the existence of line spectra

• Discovery of the proton

Answer explanation

Niels Bohr won the Nobel Prize for his explanation of the structure of the hydrogen atom and the existence of line spectra, making it the ideal topic for Piper's report.