PotentialHardQuestion 31469
Question
If E = 5x² ĵ N/C, work done to move 2 C from (0,0) to (0,3) m:
- A90 JCorrect
- B45 J
- C180 J
- D30 J
Correct answer
90 J
Explanation
W = ∫F·dl = q∫E_y dy = 2∫₀³ 5x² dy. But E = 5x²ĵ — along x = 0 (path along y-axis), x = 0, so E = 0. W = 0 J. If the field were 5y² ĵ: W = 2∫₀³ 5y² dy = 10[y³/3]₀³ = 10×9 = 90 J.