JEE MainPhysicsElectrostatics
A point charge 5 C is moved from an initial position A(2, 3, 0) m to a final position B(5, 7, 0) m in a region of uniform electric field E = (10 i + E_y j ) V/m . If the total work done by the electric field on the charge is 350 J , the value of the y -component of the electric field, E_y , is
Options
- A-25 V/m
- B10 V/m
- C17.5 V/m
- D0 V/m
Correct answer
B. 10 V/m
Step-by-step solution
The displacement vector of the charge is given by r = r _B - r _A = (5 - 2) i + (7 - 3) j = 3 i + 4 j m . The work done by the uniform electric field is W = q( E r ) . Substituting the given values: 350 10⁻⁶ = 5 10⁻⁶ [ (10 i + E_y j ) (3 i + 4 j ) ] 70 = 10(3) + E_y(4) 70 = 30 + 4E_y 4E_y = 40 E_y = 10 V/m Answer: 10 V/m