A charge of 24 C passes through a circuit every 9 s. If the circuit can generate 6 W of power, what is the circuit's resistance?

2 Answers
May 30, 2017

Resistance is defined as the ability of the conductor to obstruct the flow of electric current through it. Resistance is basically defined by Ohm's Law as:-
V=IR

Explanation:

In the given question, we have:-
Charge = 24C = Q
Time = 9s = t

Rate of flow of current thorugh a cross-section of a conductor is givem by the following relation:-

Q = It where,
Q = Given charge
I = Current that flows
t = time (in second)

So, putting above stated values in this relation, we get:-

24 = I . 9
or I = 24 / 9 A

Power is defined as the ability to do work. Power is given by the formula:-

P = VI where,
P = Power in watt
V = Potential difference across the circuit
I = Current through the circuit

Putting values in the relation, we get:-

6 = V . 24/9
or V = 6*9/24 V

As stated above, the expression for Ohm's Law gives resistance as:-
R = V/I

Hence, using the values obtained for V and I , we get:-

R = 6 X 9/ 24 * 9/24
or R = 0.84 Ω

Hence, the resistance of the circuit is 0.84 Ω.

May 30, 2017

The answer is =843.75mOmega

Explanation:

We apply the equation

Q=It

The charge is Q=24C

The time is t=9s

The current is I=Q/t=24/9=8/3A

The power

P=UI

But according to Ohm's Law

U=RI

So,

P=RI*I=RI^2

So,

the resistance is R=P/I^2

=6/(8/3)^2=0.84375Omega