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Question 18M.2.HL.TZ1.c.ii

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Date May 2018 Marks available [Maximum mark: 2] Reference code 18M.2.HL.TZ1.c.ii
Level HL Paper 2 Time zone TZ1
Command term Calculate Question number c.ii Adapted from N/A
c.ii.
[Maximum mark: 2]
18M.2.HL.TZ1.c.ii

Hydrogen atoms in an ultraviolet (UV) lamp make transitions from the first excited state to the ground state. Photons are emitted and are incident on a photoelectric surface as shown.

M18/4/PHYSI/HP2/ENG/TZ1/08

The electric potential of the photoelectric surface is 0 V. The variable voltage is adjusted so that the collecting plate is at –1.2 V.

An electron is emitted from the photoelectric surface with kinetic energy 2.1 eV. Calculate the speed of the electron at the collecting plate.

[2]

Markscheme

kinetic energy at collecting plate = 0.9 «eV»

speed = « 2 × 0.9 × 1.6 × 10 − 19 9.11 × 10 − 31 » = 5.6 × 105 «ms–1»

 

Allow ECF from MP1

[2 marks]

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