Potential Difference Physics Example 3

Follow the full solution, then compare it with the other examples linked below.

medium

12 \text{ V}

battery drives

3 \text{ A}

of current through a resistor. Find the resistance and the power dissipated.

1
Apply Ohm's law to find the resistance: $R = \frac{V}{I} = \frac{12}{3} = 4 \text{ } \Omega$ .
2
Calculate the power dissipated using $P = VI$ : $P = 12 \times 3 = 36 \text{ W}$
3
Verify using the alternative formula: $P = I^2 R = 3^2 \times 4 = 9 \times 4 = 36 \text{ W}$ . Consistent.

Answer

R = 4 \text{ } \Omega, \quad P = 36 \text{ W}

Ohm's law (

V = IR

) and the power formula (

P = VI

) are the two most fundamental relationships in circuit analysis. Power can equivalently be expressed as

P = I^2R

P = \frac{V^2}{R}

About Potential Difference

The difference in electric potential between two points, equal to the work done per unit charge moving between them.

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