A charged wire is bent in the form of a semi circular arc if radius a. If charge per unit length is lambda C/m, the electric field at the centre O is?

Q. 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 :

Q. A uniformly changed wire is bent in the form of circle, of radius $a$. If charge per unit length is $\lambda \text{C/m}$, the electric field at the centre $O$ is,

Q. A wire, of length $L(=20cm)$, is bent into a semi-circular arc. If the two equal halves, of the arc, were each to be uniformly charged with charges $\pm Q,[|Q|={10}^3{ϵ}_0$ Coulomb where ${ϵ}_0$ is the permittivity (in SI units) of free space] the net electric field at the centre O of the semi-circular arc would be :

Q. A rod is bent into a semi-circular arc of radius R. The rod has a uniform linear charge distribution $\lambda$. The potential at the centre of the arc, point P is

Q. An infinite long thread carries a charge uniformly spread over its length. It is bent in the form as shown. If the charge per unit length is $\lambda$, the electric field at point $O$ is