A plane mirror is placed at the bottom of the tank containing a liquid of refractive index J.1.P is a small object at a height h above the mirror, an observer O-vertically above P outside the liquid. See p and its image in the mirror. The apparent distance between these two will be ____________.

Two plane mirrors are at right angles to each other. A man stands between them and combs hair with his right hand. In how many of the images will he be seen using his right-hand __________.

The anode plate in an experiment on photoelectric effect is kept vertically above the emitter plate. Light source is put on. An electric field is switched on which has vertically downward direction.

An oil drop carrying a charge q has a mass of m kg. It is falling freely in the air with terminal speed v. The electric field required to make the drop move upwards with the same speed is ______________.

The existence of E.M. waves was confirmed experimentally by __________________.

The Q factor of an a.c circuit containing a resistance R, inductance L and capacitor C is ________________.

If a current I is flowing in a straight wire parallel to the x-axis and magnetic field is in the y-axis then the wire experiences in _________________.

The emf of a battery is 3 volts and internal resistance 0.125 \(\Omega \) . The difference of potential at the terminal of battery when connected across an external resistance of 1 \(\Omega \) is ______________.

The potential due to a single point charge falls as

Eight mercury droplets having a radius of 1 mm and charge of 0.066 PC each merge to form one droplet. Its potential is _____________