A light ray travels through a transparent cooling liquid and enters the protective window of an optical sensor at a non-zero angle to the normal.
| Material | Wavelength of the light |
|---|---|
| cooling liquid | 510 nm510\ \mathrm{nm}510 nm |
| protective window | 420 nm420\ \mathrm{nm}420 nm |
Which comparison is correct for the light as it enters the protective window?
Its speed is greater in the protective window, and the ray bends towards the normal.
Its speed is greater in the protective window, and the ray bends away from the normal.
Its speed is smaller in the protective window, and the ray bends towards the normal.
Its speed is smaller in the protective window, and the ray bends away from the normal.
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.