A student draws an emergent ray using two pencil marks that are very close together. The marks are large compared with the distance between them.
Which change most directly reduces the uncertainty in the direction of the drawn ray?
Use a brighter lamp and keep the marks close together.
Repeat the angle reading without changing the pencil marks.
Use smaller marks and place the marks further apart.
Use a thicker pencil and place the marks further apart.
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.