In a transistor, in common emitter configuration, the ratio of power gain to voltage gain is

A galvanometer of resistance $$20 ~\Omega$$ gives a deflection of 5 divisions when $$1 \mathrm{~mA}$$ current flows through it. The galvanometer scale has 50 divisions. To convert the galvanometer into a voltmeter of range 25 volt, we should connect a resistance of

The equation of simple harmonic progressive wave is given by $$y=a \sin 2 \pi(b t-c x)$$. The maximum particle velocity will be half the wave velocity, if $$\mathrm{c}=$$

Five current carrying conductors meet at a point '$$\mathrm{O}$$' as shown in figure. The magnitude and direction of the current in conductor '$$O P$$' is