Question

A total charge of 9.0 mC passes through a cross-sectional area of a nichrome wire in 3.6s. The number of electrons passing through the cross-sectional area in 10s is

Answer 1

Answer:

n = 1.56 x 10¹⁷ electrons

Explanation:

First of all, we will calculate the current passing through wire:

$I = \frac{q}{t}$

where,

I = current = ?

q = charge = 9 mC = 0.009 C

t = time = 3.6 s

Therefore,

$I = \frac{0.009\ C}{3.6\ s}\\\\I = 0.0025\ A = 2.5\ mA$

Now, for the same current in 10 s time the charge will be:

q = It = (0.0025 A)(10 s)

q = 0.025 C

Now, the number of electrons can be given as:

$q = ne\\\\n = \frac{q}{e}$

where,

n = no. of electrons = ?

q = charge = 0.025 C

e = charge on single electron = 1.6 x 10⁻¹⁹ C

Therefore,

$n = \frac{0.025\ C}{1.6\ x\ 10^{-19}\ C}$

n = 1.56 x 10¹⁷ electrons