# Calculate the total number of electrons flowing through a circuit in 20 mins and 40 s, if a current of 40 μA flows through the circuit.[1 e– = 1.6 × 10-19 C] - Physics

Sum

Calculate the total number of electrons flowing through a circuit in 20 mins and 40 s, if a current of 40 μA flows through the circuit.
[1 e = 1.6 × 10-19 C]

#### Solution

Number of electrons = n = ?

Time = t = 20 min 40 s

t = (20 × 60 + 40) s

t = 1240 s

Electric current = I = 40 μA

I = 40 × 10-6 A

Charge on one electron = 1 e = 1.6 × 10-19 C

Charge = Q = ?

I = "Q"/"t"

Q = It

Q = 40 × 10-6 × 1240

Q = 49600 × 10-6 C

Q = 4.96 × 10-2 C

Now Q = n (charge on 1 electron) = ne

4.96 × 10-2 = n × 1.6 × 10-19

n = (4.96 xx 10^-2)/(1.6xx10^-19)

n = 3.1 × 1017 electrons

Concept: Types of Circuits: Simple Circuit
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#### APPEARS IN

Goyal Brothers Prakashan Class 9 A New Approach to ICSE Physics Part 1
Chapter 10 Electricity and Magnetism – 1
Unit I Practice Problems 3 | Q 1