DP Physics (first assessment 2025)

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Question 19M.1A.HL.TZ2.38

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Date May 2019 Marks available [Maximum mark: 1] Reference code 19M.1A.HL.TZ2.38
Level HL Paper 1A Time zone TZ2
Command term Question number 38 Adapted from N/A
38.
[Maximum mark: 1]
19M.1A.HL.TZ2.38

Photons of a certain frequency incident on a metal surface cause the emission of electrons from the surface. The intensity of the light is constant and the frequency of photons is increased. What is the effect, if any, on the number of emitted electrons and the energy of emitted electrons?

[1]

Markscheme

B

Examiners report

A low discrimination index with the majority of candidates choosing option D when B is correct. Students tend to link the intensity of light to the number of photons but forget that it is the energy (per unit time per unit area) of the light so if the photon energy increases (frequency increases) then the number of photons must decrease.

Syllabus sections