The linear charge density on a dielectric ring of radius R is varying with θ as λ=λ0cos⁡θ2, where λ0 is constant. The potential at the centre O of ring [in volt] is_____________

The charge on the infinitesimal elements of arc which subtend an angle dθ at the centre of the ringdQ=λRdθ=λ0cos⁡θ2RdθPotential at the centre of ring due to charge dQdV=14πϵ0dQR=λ0cos⁡θ2⋅Rdθ4π∈0RV=∫dV⇒V=λ04πϵ0∫02π cos⁡θ2dθ=λ04πϵ0sin⁡θ21202π=0V