The difference of potential between the terminals of cells is 2.2 volts. When a 4ohm resistor is connected across the terminals of this cells, the potential difference is 2 volts. What is the internal resistance of the cell?

Josephwale

5 years ago

Wrong answer: the answer is E.... r=R(E-V)/V that's the quickest formula for internal resistance adapted from The science physics pg 325 left side

Truss

1 year ago

We can determine the internal resistance of the cell using Ohm's law and the formula for terminal voltage:

V = E - Ir

where:

(terminal voltage when connected to the resistor)

(emf of the cell)

= internal resistance (to be found)

= current flowing through the circuit

(external resistor)


Step 1: Find the current using Ohm’s Law

I = \frac{V}{R} = \frac{2.0V}{4\Omega} = 0.5A

Step 2: Use the emf equation

E = V + Ir

2.2V = 2.0V + (0.5A \times r)

Step 3: Solve for

0.2V = 0.5A \times r

r = \frac{0.2V}{0.5A} = 0.4\Omega

Answer:

C. 0.40 ohms

Idowuayomideolaniyi

1 year ago

mistake in question/workings. you used 0.2 Instead of 2.2

Babliwa

3 years ago

From the formula you gave [r=R(E-V)] /V, the answer is still C= 0.4ohms

Aniwen

1 year ago

I’m trying to submit is not working

OsagieN

2 years ago

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