A transparent ceramic cover is placed in the path of a beam of electromagnetic radiation from a scientific instrument. In the vacuum before the cover, the beam has a wavelength of 750 nm750\ \mathrm{nm}750 nm and travels at 3.0 × 108 m/s. Inside the cover, it travels at 1.8 × 108 m/s. At the boundary, the number of oscillations passing each point per second is unchanged.
Which value gives the wavelength of the radiation inside the ceramic cover?
450 nm450\ \mathrm{nm}450 nm
1250 nm1250\ \mathrm{nm}1250 nm
750 nm750\ \mathrm{nm}750 nm
300 nm300\ \mathrm{nm}300 nm
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.