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Physics Question 49 – JEE-MAIN 2026

A three coulomb charge moves from the point (0,2,5) to the point (5,1,2) in an electric field expressed as E=2xi^+3y2j^+4k^ N/C. The work done in moving the charge is _______ J.

The work done by an electric field on a charge is given by the line integral of the electric force over the path.

Step 1: Identify the formula for work done✦ Active

The work done W by an electric field E on a charge q moving from an initial point A to a final point B is given by the line integral:

W=qABEdl

Given charge q=3 C. The electric field is E=2xi^+3y2j^+4k^ N/C. The differential displacement vector is dl=dxi^+dyj^+dzk^. The initial point is A=(0,2,5) and the final point is B=(5,1,2).

Step 2: Calculate the dot product and set up the integral○ Expand

First, calculate the dot product Edl:

Edl=(2xi^+3y2j^+4k^)(dxi^+dyj^+dzk^)=2xdx+3y2dy+4dz

Now, set up the integral for the work done:

W=qAB(2xdx+3y2dy+4dz) W=q(xAxB2xdx+yAyB3y2dy+zAzB4dz) W=3(052xdx+213y2dy+524dz)
Step 3: Evaluate the integrals and find the total work done○ Expand

Evaluate each definite integral:

052xdx=[x2]05=5202=25 213y2dy=[y3]21=13(2)3=1(8)=9 524dz=[4z]52=4(2)4(5)=8(20)=28

Sum the results and multiply by the charge q=3 C to find the total work done:

W=3(25+9+28)=3(62)=186 J
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