Question

2. If 300 mA current passes through a lamp, how many electrons will pass through it in 1 minute? ​

Answer 1

Answer:

1.125 × 10 ^ 20 electrons.

Explanation:

I = 300 mA = 0.3 A

time,T = 60 secs

Net charge, Q = I × T

= 0.3 × 60

= 18 coulomb

Now,

Net charge

No. of electrons = —————————

Charge on one electron

= 18 / 1.6 × 10 ^ -19

= 1.125 × 10 ^ 20 electrons

Hope it helps you :)

Answer 2

Given:

• The current = 300 mA
• Time = 1 min

To Find:

• The number of electrons passing through the lamp in one minute.

Solution:

First, let us convert the units of current and time.

1. Current = 300 mA = 300/1000 A = 300 × $10^{-3}$ A {1 A = 1000 mA}

2. Time = 1 min = 60 secs. { one minute = 60 seconds}

Now We know that,

I = q/t → {equation 1}

Where "I" is current, "q" is the charge, and "t" is the time taken.

We know that " charge = no: of electrons × charge of electrons (e = 1.6 × $10^{-19}$ C)"

∴ q = n×e substitute this value in equation 1 for "q". We get,

⇒ I = (n×e)/t

On rearranging the above equation in terms of "n" we get,

⇒ n = (I×t)/e

Substitute the values in the above equation. We get,

⇒ n = (300× $10^{-3}$× 60)/1.6×$10^{-19}$  {multiplying the terms in numerator}

⇒ n = 18/ 1.6 × $10^{-19}$ {dividing the terms}

⇒ n = 11.25 × $10^{-19}$ = 1.125 × $10^{20}$

∴ The number of electrons passing through the lamp in one minute = 1.125 × $10^{20}$.