In a fluorescent lamp choke (a small transformer) 100 V of reverse voltage is produced when the choke current changes uniformly from 0.25 A to 0 in a duration of 0.025 ms. The self-inductance of the choke (in mH) is estimated to be ________.

A body of mass m = 10 kg is attached to one end of a wire of length 0.3 m. The maximum angular speed (in rad s^–1) with which it can be rotated about its other end in space station is :
(Breaking stress of wire = 4.8 × 10⁷ Nm^–2 and
area of cross-section of the wire = 10^–2 cm²) is:

In the given circuit diagram, a wire is joining points B and D. The current in this wire is :

Two particles of equal mass m have respective
initial velocities $$u\widehat i$$ and $$u\left( {{{\widehat i + \widehat j} \over 2}} \right)$$.
They collide completely inelastically. The energy lost in the process is :