Question

2.5 ampere current is flowing in awire How much charge will flow in the wire 20 minute ? Also find the number of elections flowing through it per second

Answer 1

GIVEN:

• Current , I = 2.5 A
• Time, t = 20 minute

TO FIND:

• Charge, q
• Number of electrons flowing per second, n

FORMULA:

I = q/t

q = ne

Where n is the number of electrons.

e is the charge of electron.

e = 1.6 × 10^-19 C

SOLUTION:

STEP 1: To change time in standard units.

• SI unit of time is second.

• 1 minute = 60 seconds.

• 20 minutes = 20 × 60 seconds.

• Time , t = 1200 seconds.

STEP 2: To find charge

$I = \dfrac{q}{t} \\ \\\implies 2.5 = \dfrac{q}{1200} \\ \\\implies q = 2.5 \times 1200 \\ \\ \implies q = 3000 \: coulomb$

Charge flowing is 3000 C.

STEP 3: To find number of electrons

$q = ne \\ \\\implies 3000 = n \times 1.6 \times {10}^{ - 19} \\ \\\implies n = \dfrac{3000}{1.6 \times {10}^{ - 19} } \\ \\ \implies n = \dfrac{3000}{1.6} \times {10}^{19} \\ \\\implies n = \dfrac{3000 \times 10}{1.6 \times 10} \times {10}^{19} \\ \\\implies n = \dfrac{30000}{16} \times {10}^{19} \\ \\\implies n = 1875 \times {10}^{19} electrons$

1875 × 10¹⁹ electrons flow for 1200 seconds.

Then number of electrons flowing per second will be ,

$n = \dfrac{1875 \times {10}^{19} }{1200} \\ \\\implies n = 1.5625 \times {10}^{19} electrons \: per \: second$

Number of electrons flowing per second is 1.5625 × 10¹⁹ electrons.

ANSWER:

• Charge flowing is 3000 C.

• Number of electrons flowing per second is 1.5625 × 10¹⁹ electrons.