Question

A current of 5mA is passing through a wire. How many electrons are passing per minute through any cross section of the wire?​

Answer 1

Answer:

No.of Free Electrons ( n ) =

18.75 ×10^17 ê

Explanation:

★ CURRENT ELECTRICITY ★

GIVEN ;

» CURRENT ( i ) = 5 mA

» Time ( t ) = 1 minute = 60 sec.

» Electric Charge ( e ) = 1.6 × 10^-19 C

★ No. of Free Electrons ( n ) = ???

___ [ BY USING FORMULA ] ________

[ $i \: = \frac{ \: n \: \times \: e }{t}$ ]

★ no. of free electrons ( n ) =[CURRENT ( i ) × TIME ( t ) ] / ELECTRIC CHARGE (e)

» n = [ 5 × 10-³ × 60 ] / 1.6 × 10^-19

» n = [ 300 × 10-³ ] × 6.25 × 10^18

» n = [ 0.3 ] × 0.625 × 10^19

» n = 0.1875 × 10^19

★ → n = 18.75 × 10^17 ê ← ★

_________________________________________

ANSWER :- Hence ; NO. OF FREE ELECTRONS passing through 5mA current in 1 minute is ;

♣ n = 18.75 × 10^17 ë ♥

Answer 2

I = 5 mA = 5 × 10-³

t = 1 min = 60 sec

e = 1.6 × 10-¹⁹ C

Now

I = Q/t

and Q = ne

So I = ne/t

5 × 10-³ = (n × 1.6 × 10-¹⁹)/60

n = 0.187 × 10¹⁹

n = 1.87 × 10¹⁸ e‐