Two stationary spacecraft send pulses to the same detector. One sends a radio pulse and the other sends a gamma-ray pulse. The radio pulse is emitted before the gamma-ray pulse, but both pulses reach the detector at the same instant after travelling only through a vacuum.
Which statement about the distances travelled by the pulses is correct?
The pulses travelled the same distance.
The distances travelled by the pulses cannot be compared.
The radio pulse travelled a greater distance.
The gamma-ray pulse travelled a greater distance.
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.