Potential Difference Physics Example 4

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Example 4

medium
Two points A and B in an electric field have potentials VA=100 VV_A = 100 \text{ V} and VB=40 VV_B = 40 \text{ V}. What is the potential difference from A to B? How much work is done moving a 2×10−6 C2 \times 10^{-6} \text{ C} charge from B to A?

Solution

  1. 1
    Potential difference: VAB=VA−VB=100−40=60 VV_{AB} = V_A - V_B = 100 - 40 = 60 \text{ V}.
  2. 2
    Work done moving charge from B to A: W=q⋅VAB=2×10−6×60=1.2×10−4 JW = q \cdot V_{AB} = 2 \times 10^{-6} \times 60 = 1.2 \times 10^{-4} \text{ J}

Answer

VAB=60 V,W=1.2×10−4 JV_{AB} = 60 \text{ V}, \quad W = 1.2 \times 10^{-4} \text{ J}
The potential difference between two points determines the work done per unit charge moving between them. Moving a positive charge from lower to higher potential requires work input.

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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Example 2 medium

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Example 3 medium

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Example 5 hard

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