Assuming that junction diode is ideal, the current in arrangement shown in figure

Four thin metal rods each of mass ' $M$ ' and length ' $L$ ', are welded end to end to form a square. The moment of inertia of the system about an axis passing through the centre of the square and perpendicular to its plane is

Considering interference between two sources of intensities ' I ' and ' 4 I ', the intensity at a point where the phase difference is $\pi$ is $(\cos \pi=-1)$

If number of turns per unit length in a solenoid is tripled, the self inductance of solenoid will