What will be energy used by the battery if the battery has to drive 6.28 x 1018 electrons with potential difference of 20 V across the terminal?
A. 5 joules
B. 10 joules
C. 15 joules
D. 20 joules
Answer: Option D
Solution (By Examveda Team)
The correct answer is D: 20 joulesHere's why:
Energy used by a battery is related to the charge it moves and the voltage across it.
The formula we need to use is: Energy (E) = Charge (Q) x Voltage (V)
We are given the voltage (V) as 20 V.
We need to find the charge (Q).
We know the number of electrons (6.28 x 1018).
The charge of a single electron is approximately 1.6 x 10-19 Coulombs.
To find the total charge (Q), we multiply the number of electrons by the charge of a single electron:
Q = (6.28 x 1018) x (1.6 x 10-19) Coulombs
Q ≈ 1 Coulomb
Now we can calculate the energy:
E = Q x V
E = 1 Coulomb x 20 V
E = 20 Joules
Therefore, the energy used by the battery is 20 joules.
This Question Belongs to Electrical Engineering >> Current Electricity
Number of electrons: n=6.28x10^{18}
Potential difference: V=20V
Elementary charge: e=1.602x 10^{-19}
The charge due to electrons is given by Q=ne.
The energy E required to move a charge Q through a potential difference V is given by E=QV.
E=neV = 6.28x10^{18} x 1.602x 10^{-19} x 20
E = 20 joules
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