Which one of the following p-V diagram is correct for an isochoric process:

A magnetic dipole of magnetic moment $$\mathrm{M}$$, is freely suspended in a magnetic field of induction B. The minimum and maximum values of potential energy of the dipole, respectively are

In series LCR circuit, at resonance the peak value of current will be [$$\mathrm{E_0}$$ is peak emf, R is resistance, $$\omega \mathrm{L}$$ is inductive reactance and $$\omega \mathrm{C}$$ is capacitive]

A particle is moving along the circular path with constant speed and centripetal acceleration 'a'. If the speed is doubled, the ratio of its acceleration after and before the change is