Physics (AS & A Level) · Oct / Nov 2017 · Paper 13 · Question 32

Lightning can occur between a charged cloud and the Earth's surface when the electric field strength in the intervening atmosphere reaches 25 kN C–1. The diagram shows the electric field between the base of a cloud and the Earth's surface. What is the minimum potential difference between the Earth and the base of a cloud, 2.0 km high, for lightning to occur?

1. A12.5 MV
2. B25 MV
3. C50 MV
4. D100 MV

As printed in the paper