A diatomic molecule is formed by two atoms which may be treated as mass points `m_1` and `m_2` joined by a massless rod of length `r`. Then the moment of inertia of molecule about an axis passing through centre of mass and perpendicular to the rod is:

Options

A. zero
B. `(m_(1)+m_(2))r^(2)`
C. `((m_(1)m_(2))/(m_(1)+m_(2))) r^(2)`
D. `((m_(1)m_(2))/(m_(1)m_(2))) r^(2)`

Answer

C

Explanation

With respect to centre of mass, effective mass
`=(m_(1)m_(2))/(m_(1)+m_(2)), :. I=[(m_(1)m_(2))/(m_(1)+m_(2))]r^(2)`