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An electric field is given as E = 6y2z i + 12xyz j + 6xy2 k. An incremental path is given by dl = -3 i + 5 j – 2 k mm. The work done in moving a 2mC charge along the path if the location of the path is at p(0,2,5) is (in Joule)
To calculate the work done in moving a charge in an electric field, we use the formula:
[ W = q int vec{E} cdot dvec{l} ]
Where:
– ( W ) is the work done,
– ( q ) is the charge (in Coulombs),
– ( vec{E} ) is the electric field,
– ( dvec{l} ) is the differential path element.
First, we need to evaluate ( vec{E} ) at the point ( p(0, 2, 5) ):
[
E = 6y^2z hat{i} + 12xyz hat{j} + 6xy^2 hat{k}
]
Substituting ( y = 2 ) and ( z = 5 ):
1. For the ( hat{i} ) component:
[
E_x = 6(2^2)(5) = 6(4)(5) = 120
]
2. For the ( hat{j} ) component:
[
E_y = 12(0)(2)(5) = 0
]
3. For the ( hat{k} ) component:
[
E_z = 6(0)(2^2) = 0
]
Thus, at point
Answer: b
Explanation: W = -Q E.dl
W = -2 X 10-3 X (6y2z i + 12xyz j + 6xy2 k) . (-3 i + 5 j -2 k)
At p(0,2,5), W = -2(-18.22.5) X 10-3 = 0.72 J.