AQA ยท GCSE Physics

Infrared chip and gas detection GCSE Physics challenge

Can you get 100%? Use a tunable infrared camera chip to test the electromagnetic spectrum, wave calculations and selective absorption by gases.

Read how the infrared chip detects heat and gases

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Question

7 marks

Answer all parts. Show your working and give units where appropriate.

1(a)

An infrared wave has frequency 3.0 x 10^13 Hz. Calculate its wavelength in air. Use wave speed = 3.0 x 10^8 m s^-1.

[3 marks]

1(b)

Methane absorbs infrared radiation strongly in particular wavelength bands. Explain how measuring the infrared intensity before and after light passes through a gas can show that methane is present.

[2 marks]

1(c)

Each small region of the new chip can be tuned electrically to respond differently. Explain one advantage of this design when a camera must distinguish a warm wall from a methane plume.

[2 marks]

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