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Date May 2011 Marks available 1 Reference code 11M.3.SL.TZ2.3
Level Standard level Paper Paper 3 Time zone Time zone 2
Command term State Question number 3 Adapted from N/A

Question

This question is about the photoelectric effect.

State what is meant by the photoelectric effect.

[1]
a.

Light of frequency 8.7×1014Hz is incident on the surface of a metal in a photocell. The surface area of the metal is 9.0×10–6m2 and the intensity of the light is 1.1×10–3Wm–2.

(i) Deduce that the maximum possible photoelectric current in the photocell is 2.7 nA.

(ii) The maximum kinetic energy of photoelectrons released from the metal surface is 1.2 eV. Calculate the value of the work function of the metal.

[4]
b.

Markscheme

ejection of electron from metal surface following absorption of em radiation/photon;

a.

(i) energy of one photon = 6.67×10−34×8.7×1014(=5.8×10−19J);

number of electrons released from surface per second \( = \frac{{9.0 \times {{10}^{ - 6}} \times 1.1 \times {{10}^{ - 3}}}}{{5.8 \times {{10}^{ - 19}}}}\);
=1.7×1010;
current=1.7×1010×1.6×10−19;
= 2.7nA

(ii) 2.4eV or 3.9×10−19J;

b.

Examiners report

[N/A]
a.
[N/A]
b.

Syllabus sections

Additional higher level (AHL) » Topic 12: Quantum and nuclear physics » 12.1 – The interaction of matter with radiation
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