Sketch the electric field around a positive point charge.
The graph shows how potential varies with distance from the centre of a charged sphere.
Air molecules will be ionised if the electric field strength exceeds 3 × 106 V m–1.
Deduce whether air molecules will be ionised at a distance of 30 cm from the centre of this sphere.
A magician did a trick which he claimed was the most dangerous ever. He positioned himself midway between two charged spheres which were separated by a distance of about two metres. Each sphere was charged to a potential that would cause ionisation at a distance of one metre. He wore a protective suit of chain mail and a helmet consisting of a metal cage. The protective suit and helmet were earthed to a potential of 0 V.
A scientist said “there is no danger in this and I would happily do it tomorrow”.
Explain whether this statement is justified.
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