Physics · OCR H556 · Topic 4.5

Quantum physics

Photons, the photoelectric effect, wave-particle duality.

3 sub-topics
Taught in Year 12
35 practice questions
3 animated lessons

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What the specification says

Every sub-topic OCR can examine in this topic, with its reference number from the official specification. The Y12 and Y13 tags show when each sub-topic is usually taught.

4.5.1PhotonsY12
4.5.2The photoelectric effectY12
4.5.3Wave-particle dualityY12

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Easy and medium questions from this topic, each with a worked solutions and the mark for every step. All 35 questions in this topic, free, no account needed.

Waves and the particle nature of light

Easy

Photon energy · Year 12 · 4 marks

Electromagnetic radiation has wavelength

4.0 \times 10^{-7}

(a)
Calculate the energy of one photon in joules and in electronvolts.
(3)
(b)
A source emits 2.0 mW of this radiation. Calculate the number of photons emitted per second.
(1)

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Part (a)3 marks

$E = \frac{hc}{\lambda}$
$E$ ${}= 4.97 \times 10^{-19}\ \mathrm{J}$
$E = 3.11\ \mathrm{eV}$

Part (b)1 mark

$N$ ${}= 4.02 \times 10^{15}\ \mathrm{s^{-1}}$

Total4

MMethod mark: for a correct method, even with a slip.
AAccuracy mark: for a correct answer from a correct method.
BIndependent mark: for a correct fact or result on its own, with no method needed.

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Waves and the particle nature of light

Medium

The de Broglie wavelength · Year 12 · 4 marks

Electrons are accelerated from rest through a p.d. of 500 V.

(a)
Calculate the momentum of an electron.
(2)
(b)
Calculate its de Broglie wavelength.
(2)