Physics 2010 JAMB Past Questions - Question 35: A cell of emf 12 V and internal residence 4Ω is connected to an external resistor of resistance 2Ω.Find the current flow.

Correct Answer

B

Explanation

I = E/R+r = 12/2+4 = 2ATo find the current flowing through the circuit, you can use Ohm's law, which relates voltage (V), current (I), and resistance (R). Ohm's law is given by the formula:

V = I * R

Where:
V = Voltage (in volts)
I = Current (in amperes)
R = Resistance (in ohms)

In your case, the cell has an electromotive force (emf) of 12 V and an internal resistance of 4Ω. The external resistor has a resistance of 2Ω.

1. Calculate the total resistance in the circuit, which is the sum of the internal resistance (r) and the external resistance (R):

Total Resistance (R_total) = r + R
R_total = 4Ω + 2Ω
R_total = 6Ω

2. Now, use Ohm's law to find the current (I) in the circuit:

V = I * R_total
12V = I * 6Ω

3. Solve for I:

I = 12V / 6Ω
I = 2 amperes

So, the current flowing through the circuit is 2 amperes.