The increase in length due to the weight of the wire can be calculated using the formula for elongation under tension:
\( \Delta L = \frac{F L}{A Y} \), where \( F = \rho g L^2 \) is the force due to the weight, and \( Y \) is the Young's modulus.
You are given a dipole of charge \( +q \) and \( -q \) separated by a distance \( 2l \). A sphere 'A' of radius \( R \) passes through the centre of the dipole as shown below and another sphere 'B' of radius \( 2R \) passes through the charge \( +q \). Then the electric flux through the sphere A is