Question

A uniform rod of mass $6M$ and length $6l$ is bent to make an equilateral hexagon. Its mutual inductance about an axis passing through the centre of mass and perpendicular to the plane of hexagon is

• A. $5m{l}^2$
• B. $6m{l}^2$
• C. $4m{l}^2$
• D. $12m{l}^2$

Answer 1

The correct option is A $5m{l}^2$

M.I $=6\times [\frac{M{L}^2}{12}+M{\left(\frac{l}{\sqrt{3}}\right)}^2]$

$6\times [\frac{M{L}^2}{12}+M{\left(\frac{l}{\sqrt{3}}\right)}^2]$

$=6\left[\frac{M{l}^2+4m{l}^2}{12}\right]$

$=5M{L}^2$