The charge per unit length of the four quadrant of the ring is `2 lambda, -2lambda, lambda` and `-lambda` respectively. The electric field at the centre is:

The linear charge density on upper half of semi-circular section of ring is lambda and that at lower half is -lambda . The direction of electric field at centre O of ring is :

The linear charge density on upper half of semi-circular section of ring is lambda and that at lower half is -lambda . The direction of electric field at centre O of ring is :

A charged wire is bent in the form of a semicircular arc of radius a. If charge per unit length is lambda coulomb/metre, the electric field at the centre O is

A semi-cricular arc of radius a is charged unformly and the charge per unit length is lambda . The electric field at the centre is

A half ring of radius R has a charge of lambda per unit length. The electric force on 1C charged placed at the center is

A semicircular wire is uniformly charged with linear charge density dependent on the angle theta from y -direction as lambda=lambda_(0) |sin theta| , where lambda_(0) is a constant. The electric field intensity at the centre of the arc is

Show that the area of the triangle with vertices (lambda, lambda-2), (lambda+3, lambda) and (lambda+2, lambda+2) is independent of lambda .