CAIE IGCSE Physics 3.3.6 Speed of EM waves in a vacuum is 3.0 ×

Practise using 3.0 x 10^8 m s^-1 for electromagnetic waves in vacuum or air, including delay and refractive-index calculations.

Exam points

state 3.0 x 10^8 m s^-1 as the speed of EM waves in a vacuum or air
calculate signal delay using distance and c, including round trips when required
use n = c/v to find light speed in glass or oil and give units correctly

[Maximum number: 2]

State the speed in a vacuum of
1. microwaves
2. X-rays

$13 \times 10^{8} \mathrm{~m} / \mathrm{s}$

B1

$23 \times 10^{8} \mathrm{~m} / \mathrm{s}$

B1

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