Question

An electron (charge $ =1.6\times {{10}^{-19}}C $ ) is meaning in a circle of radius $ 5.1\times {{10}^{-11}}m $ at a frequency of $ 6.8\times {{10}^{15}} $ revolution/s. The equivalent current is approximately

• A. $ 5.1\times {{10}^{-3}}A $
• B. $ 6.8\times {{10}^{-3}}A $
• C. $ 1.1\times {{10}^{-3}}A $
• D. $ 2.2\times {{10}^{-3}}A $

Answer 1

Answer: (C)

Charge $ Q=it $ $ ne=it $ $ i=\frac{ne}{t} $ $ =\frac{6.8\times {{10}^{15}}\times 1.6\times {{10}^{-19}}}{1} $ $ =1.08\times {{10}^{-3}}A $ $ =1.1\times {{10}^{-3}}A $