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E.2 Quantum physics (HL only) - IB Questionbank | RevisionDojo

Practice E.2 Quantum physics (HL only) with authentic IB Physics exam questions for both SL and HL students. This question bank mirrors Paper 1A, 1B, 2 structure, covering key topics like mechanics, thermodynamics, and waves. Get instant solutions, detailed explanations, and build exam confidence with questions in the style of IB examiners.

Paper

Level

Question 1

HLPaper 2

In a photoelectric experiment, the stopping potential is measured as $1.2\ \text{V}$ when the incident light frequency is $7.0 \times 10^{14}\ \text{Hz}$ .

Write the equation relating stopping potential $V_s$ , frequency $f$ , work function $\Phi$ , and Planck’s constant $h$ .

[1]

Calculate the maximum kinetic energy of emitted photoelectrons.

[1]

Determine Planck’s constant $h$ given the work function $\Phi = 2.0\ \text{eV}$ . (1 eV = $1.60 \times 10^{-19}$ J)

[3]

Explain how the photoelectric effect demonstrates the quantized nature of light.

[2]

Question 2

HLPaper 2

The diagram shows an experimental setup used to investigate the photoelectric effect. Light is incident on a metal surface in a vacuum. A variable potential difference is applied between the collector and emitter. The current and voltage are measured using an ammeter and voltmeter.

State one observation from the photoelectric experiment that cannot be explained by the wave theory of light.

[1]

Explain how this observation supports the photon model of light.

[2]

Describe how the stopping voltage is determined using the setup shown.

[2]

When light of frequency $6.2 \times 10^{14}$ Hz is shone on a metal surface, electrons are emitted. The stopping potential is measured to be 0.85 V. Determine the work function of the metal in eV.

[3]

The intensity of the incident light is increased but its frequency remains the same. Discuss the effect of this change on the photoelectric current and the stopping potential.

[2]

Outline two assumptions of the photon model used to explain the photoelectric effect.

[2]

Question 3

HLPaper 1A

What is the unit of Planck's constant?

Question 4

HLPaper 2

An electron beam is accelerated through a potential difference of $400\ \text{V}$ . It is directed onto a crystal, producing a diffraction pattern with a first minimum at an angle of $15^\circ$ .

Calculate the de Broglie wavelength of the electrons. (Use $m_e = 9.11 \times 10^{-31}\ \text{kg}$ , $h = 6.63 \times 10^{-34}\ \text{J s}$ , $e = 1.60 \times 10^{-19}\ \text{C}$ .)

[3]

Using Bragg’s law $n \lambda = 2 d \sin \theta$ with $n=1$ , calculate the lattice spacing $d$ of the crystal.

[2]

Explain how the electron diffraction experiment provides evidence for the wave nature of matter.

[2]

Question 5

HLPaper 1A

Which experiment demonstrated that light behaves as particles?

Question 6

HLPaper 1A

Which experiment provided direct evidence for the wave nature of electrons?

Question 7

HLPaper 1A

Which observation in Compton scattering provides evidence for the particle nature of light?

Question 8

HLPaper 1A

Einstein explained the photoelectric effect by proposing that light energy is quantized in packets called:

Question 9

HLPaper 1A

Which change would increase the maximum kinetic energy of electrons emitted in the photoelectric effect?

Question 10

HLPaper 1A

Which of the following observations in the photoelectric effect provides evidence for the particle nature of light?

E.2 Quantum physics (HL only) Questionbank