JEE PYQ: Current Electricity Question 5
Question 5 - 2021 (17 Mar 2021 Shift 1)
A current of 10 A exists in a wire of cross-sectional area of $5,\text{mm}^2$ with a drift velocity of $2 \times 10^{-3},\text{ms}^{-1}$. The number of free electrons in each cubic meter of the wire is
(1) $2 \times 10^{6}$
(2) $625 \times 10^{25}$
(3) $2 \times 10^{25}$
(4) $1 \times 10^{23}$
Show Answer
Answer: (2)
Solution
$i = neAv_d$. $10 = n \times 1.6 \times 10^{-19} \times 5 \times 10^{-6} \times 2 \times 10^{-3}$. $n = 0.625 \times 10^{28} = 625 \times 10^{25}$.
BETA
