Electron energy levels – MCQs (set 1)

The discharge spectrum of a particular gas contains one line of frequency 5.0 x 10¹⁴ Hz. This line could be caused by photons of energy...

• 3.3 x 10¹⁹ J

• 1.3 x 10^-19 J

• 1.1 x 10^-19 J

• 3.3 x 10^-19 J

• 5.3 x 10^-19 J

The gas in a discharge tube connected to a high voltage (EHT) power supply emits light with specific frequencies. Which of the following is FALSE for this situation?

• The atoms in the discharge tube are thought of as free atoms

• The power supply provides energy to excite the atoms in the gas

• The electrons in the excited gas are in their ground state

• Photons of only certain discrete energies will be emitted by the gas

• If the power supply is switched off, the gas will not emit light

The wavelength of a photon is 700 nm. Which line of the table gives the correct calculations for the frequency and energy of the photon in joules and eV?

• A

• B

• C

• D

Strong white light is shone through the gas in a discharge tube. The emerging spectrum, when examined with a diffraction grating, shows some black lines. This is because...

• black light is a component of the white light spectrum.

• the white light source had certain frequencies missing.

• certain frequencies in the white light spectrum are absorbed by atoms in the gas.

• energy is absorbed to ionize some of the atoms in the gas.

• certain frequencies in the spectrum are used to make excited gas atoms return to their ground state.

Which of the following electron transitions would cause a photon with the shortest wavelength to be emitted?

• n = 2 → n = 1

• n = 3 → n = 2

• n = 4 → n = 1

• n = 4 → n = 3

When visible light from the Sun is examined by a light frequency analyzer some frequencies are found to be missing. This is because...

• the Sun’s atmosphere reflects certain frequencies and does not allow them to leave the Sun’s surface.

• the free atoms from certain gases in the Sun’s atmosphere absorb particular frequencies.

• the radiation created at the Sun’s surface does not include all the visible frequencies.

• some frequencies use up their energy in travelling through space.

• interference patterns in space use up some of the radiated frequencies.

The diagram below shows three possible energy levels within the hydrogen atom. Which of the transitions I, II and III would emit light with a frequency greater than 4.4 x 10¹⁴ Hz?

• A) I and II and III

• B) I and III

• C) II and III

• D) I and II

• E) I only

The diagram below shows some of the energy levels in a mercury atom. Which of the following frequencies (rounded to one decimal place) could not occur in the emission spectrum of mercury?

• A) 5.1 x 10¹⁴ Hz

• B) 2.1 x 10¹⁵ Hz

• C) 4.3 x 10¹⁴ Hz

• D) 1.2 x 10¹⁵ Hz

• E) 3.9 x 10¹⁴ Hz

The diagram below shows the energy levels in a certain atom. Which of the transitions I, II and III would provide radiation capable of releasing photoelectrons from a metal where the work function is 3.3 x 10^-19 J?

• A) I and II and III

• B) I and II

• C) II and III

• D) III only

• E) I only

A pupil studying the energy level diagram for a certain element makes the following statements about the diagram shown below: Statement I: Transition Y will emit photons of the highest frequency. Statement II: Photon X will have the longest wavelength. Statement III: If the electron is in the lowest level, the atom is ionised. Which of these statements is/are TRUE?

• A) I and II and III

• B) I and III

• C) II and III

• D) I and II

• E) I only