Question

An electron moves in a circle of radius 1.0 cm with a constant speed of $4.0\times {10}^{6}m/s,$ the electric current at a point on the circle will be :
$(e=-1.6\times {10}^{-19}C)$

• A. $1\times {10}^{-11}\Omega$
• B. $1.1\times {10}^{-7}\Omega$
• C. $5.1\times {10}^{-7}\Omega$
• D. $2.1\times {10}^{-7}\Omega$

Answer 1

The correct option is A $1\times {10}^{-11}\Omega$

Using the relation

$i=\frac{q}{t}=\frac{electroniccharge}{timeperiod}=\frac{e}{t}$

Hence, $t=\frac{2\pi r}{v}$

So, $I=\frac{e}{2\pi /v}$

$=\frac{eV}{2\pi v}$

$=\frac{(1.6\times {10}^{-19})(4\times {10}^6)}{2\times 314\times 1.0\times {10}^{-2}}$

$=1\times {10}^{-11}\Omega$