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CUET · PHYSICS · PYQ PAPER 2025

A charge of \( 9 \mu C \) is given a displacement of \( \vec{r} = (4\hat{i} + 5\hat{j}) \text{ m} \) in an electric field \( \vec{E} = (5\hat{i} + 4\hat{j}) \text{ N/C} \). The work done in the process is

  1. A \( 4.5 \times 10^{-4} \text{ J} \)
  2. B \( 9.0 \times 10^{-4} \text{ J} \)
  3. C \( 1.8 \times 10^{-4} \text{ J} \)
  4. D \( 3.6 \times 10^{-4} \text{ J} \)
Verified Solution

Answer & Solution

Correct Answer

(D) \( 3.6 \times 10^{-4} \text{ J} \)

Step-by-step Solution

Detailed explanation

\( W = q (\vec{E} \cdot \vec{r}) \) \( W = (9 \times 10^{-6} \, \text{C}) ((5\hat{i} + 4\hat{j}) \cdot (4\hat{i} + 5\hat{j}) \, \text{N/C} \cdot \text{m}) \) \( W = (9 \times 10^{-6}) ((5)(4) + (4)(5)) \) \( W = (9 \times 10^{-6}) (20 + 20) \) \( W = (9 \times 10^{-6}) (40) \)…