Question

Calculate the total no. of electrons flowing through a circuit in 20 mins and 40s, if a current of 40 µA flows through the circuit (1 electron = 1.6 X10-19C)​

Answer 1

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Current Electricity

Electric Current

A current of 5 A flows th...

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Asked on December 26, 2019 by

Aditya Vaidehi

A current of 5A flows through a conductor. Calculate the number of electrons flowing through the conductor in 2s. [Take charge of electron as 1.6×10

−19

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ANSWER

Total charge that flows in 2s is given by

q=It=5×2=10C

Now, charge on one electron is given by e=1.6×10

−19

C

N= number of electrons

q=Ne

⟹N=

e

q

⟹N=

1.6×10

−19

10

⟹N=6.25×10

19

Answer 2

Answer:

The total number of electrons is found to be 3.1 × $10 ^{17}$ electrons.

Explanation:

Here we have been given that a current(I) of 40 µA is flowing through a circuit for a time (t) of 20 mins and 40 seconds. We have to find out the total number of electrons that are flowing through the given circuit at this time.

Now it has been mentioned that a charge of 1 electron is 1.6 × $10^{-19}$ C

Therefore we first find the total charge (Q) by using the following formula:

Q = I × t

I = 40 µA

t = 20 mins 40 seconds

⇒ t = 20 × 60 seconds + 40 seconds

⇒ t = 1200 seconds + 40 seconds

⇒ t = 1240 seconds

∴ Q = 40 µA × 1240 seconds

⇒ Q = 49600 × $10 ^{-6}$ C

⇒ Q = 4.96 × $10^{-2}$ C

Now a number of electrons can be found using the formula:

No. of electrons (N) = Total charge (Q) / charge of one electrons

⇒ N = $\frac{(4.96) 10^{-2} }{(1.6)10 ^{-19} }$

⇒ N = 3.1 × $10 ^{17}$ electrons.

The total number of electrons flowing through the given circuit is found to be 3.1 × $10 ^{17}$ electrons.