A student finds that less infrared energy reaches a detector when a sheet is placed in the beam. The student concludes that all the missing energy was absorbed by the sheet.
Which additional measurement is needed to test this conclusion?
The wavelength of visible light emitted by the detector.
The time taken for the infrared source to switch on.
The mass of the sheet before and after the measurement.
The infrared energy reflected by the sheet during the measurement.
84 exam-style questions on Edexcel GCSE Physics 5.2 The electromagnetic spectrum, covering 5.2.1 Electromagnetic waves and refraction in glass (core practical), 5.2.2 Groups of the electromagnetic spectrum, 5.2.3 Wavelength-dependent behaviour of EM waves, and 5.2.4 Velocities of EM waves in different substances. Each one has a worked solution and a mark scheme showing where the marks go.