The equation of an equipotential line in an electric field is ` y = 2 x `, then electric field strength vectro at `1, 2` may be .

Options

A. `4hat(i)+3hat(j)`
B. `4hat(i)+8hat(j)`
C. `8hat(i)+4hat(j)`
D. `-8hat(i)+4hat(j)`

Answer

D

Explanation

Equipotential lines are always `bot^(r)` to the electric field strength lines.
`:'` Slope of equipotential lines `=2`
`:.` Slope of electric field must be `=-1//2`
`rArr` Electric field strength vector `=8hat(i)+4hat(j)`