Two long straight parallel wires carry charges `lambda_(1) and lamba_(2)` per unit length. The distance between them is d. Calculate the magnitude of force externed on the length of one due to charge on the other.

Answer

`(lambda_(1) lambda_(2))/(2pi in_(0) d)`

Explanation

Field intensity at the location of wire 2 due to charge on wire 1 is `E = lambda_(1)//2 pi in_(0) d`
Charge on unit length of wire `2 , q = lambda_(2)`
`:.` Force on unit length of wire 2,
`f = qE = lambda_(2). (lambda_(1))/(2 pi in_(0)d) = (lambda_(1) lambda_(2))/(2pi in_(0) d)`