Magnetism And Matter — Physics STD 12 Science — Question

The transducer used in television transmission works on the principle of:

In Young's double slit experiment, carried out with light of wavelength l = 5000 Å, the distance between the slits is 0.2 mm and the screen is at 200 cm from the slits. The central maximum is at x = 0. The third maximum (taking the central maximum as zeroth maximum) will be at x equal to             

(a) 1.67 cm

(b) 1.5 cm

(c) 0.5 cm

(d) 5.0 cm

The hyper-metropia is a

(a) Short-side defect	(b) Long- side defect
(c) Bad vision due to old age	(d) None of these

If a 30 V, 90 W bulb is to be worked on a 120 V line, a resistance of how many ohms should be connected in series with the bulb

(a) 10 ohm

(b) 20 ohm

(c) 30 ohm

(d) 40 ohm

The current density (number of free electrons per m³) in metallic conductor is of the order of:

A current-carrying, straight wire is kept along the axis of a circular loop carrying a current. The straight wire:

Gases exert pressure on the walls of the container, because the gas molecules:

An electric current i enters and leaves a uniform circular wire of radius a through diametrically opposite points. A charged particle q moving along the axis of the circular wire passes through its centre at speed v. The magnetic force acting on the particle when it passes through the centre has a magnitude:

What is the resistance of a carbon resistance which has bands of colours brown, black and brown

(a) 100 W

(b) 1000 W

(c) 10 W

(d) 1 W

The speed at which the current travels in a conductor, is nearly.