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Field emission pulls electrons out of a metal using a field of about what size?
A10⁸ V/m
B10⁴ V/m
C10⁻² V/m
D10² V/m
Answer & Solution
Correct answer: A. 10⁸ V/m
Only a very strong field, of the order of 10⁸ V/m, can pull electrons out of a metal, as happens in a spark plug.
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