IIT JEE , AIEEE Forum - Physics , Electricity

cinderella_6872002

Find work done in moving a charge of 10^ -5 C from a point r1=3i+4j to another point r2=2i+6j in an electric field given by E=yi+xj.

madman

let any point P be xi+yj
E at P=xi+yj
let it be displaced to a point P1 (x+dx)i+(y+dy)j
net displacement =P1-P=dxi+dyj
assuming electric field to be constant for this interval we have
E.ds=xdx+ydy
integrating we have
integral(E.ds)=(x^2)/2+(y^2)/2
taking the limits as r1 and r2
we have V difference betweent he points = 20-25/2=15/2
work done =q*V= 15/2*10^-5
tell me if it is correct
and if it is plz rate

elessar_iitkgp

W =

F.dr =

qE.dr = q

E.dr = q

(E_xi + E_yj).(dxi + dyj) = q

(E_xdx + E_ydy)
= q

(ydx + xdy) = q_{3 x 4}

^{2 x 6}d(xy) = q [12-12] = 0

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