Chapter 12 – Electricity

Assertion: When a battery is short circuited, the terminal voltage is zero.
Reason: In short circuit, the current is zero.

Assertion: In an open circuit, the current passes from one terminal of the electric cell to another.
Reason: Generally, the metal disc of a cell acts as a positive terminal.

Electrical resistivity of any given metallic wire depends upon

Two devices are connected between two points say A and B in parallel. The physical quantity that will remain the same between the two points is

100 J of heat is produced each second in a 4Ω resistor. The potential difference across the resistor will be:

The resistivity of insulators is of the order of

An electric bulb is connected to a 220V generator. The current is 0.50 A. What is the power of the bulb?

The electrical resistance of insulators is

When electric current is passed, electrons move from:

The heating element of an electric iron is made up of:

Coulomb is the SI unit of:

Work done to move 1coulomb charge from one point to another point on a charged conductor having potential 10volt is

The effective resistance between A and B is

A student says that the resistance of two wires of same length and same area of cross section is same. This statement is correct if

A cooler of 1500 W, 200 volt and a fan of 500 W, 200 volt are to be used from a household supply. The rating of fuse to be used is

If the current I through a resistor is increased by 100% the increased in power dissipation will be (assume temperature remain unchanged)

A coil in the heater consume power P on passing current. If it is cut into halves and joined in parallel, it will consume power

If R1 and R2 be the resistance of the filament of 40 W and 60 W respectively operating 220 V, then

A metallic conductor has loosely bound electrons called free electrons. The metallic conductor is

To get 2 Ω resistance using only 6 Ω resistors, the number of them required is

Resistivity of a metallic wise depends on

Assertion: Conductors allow the current to flow through themselves.
Reason: They have free charge carriers.

Assertion: Bending of wire decrease the resistance of electric wire.
Reason: The resistance of a conductor depends on length, thickness, nature of material and temperature of the conductor.

What is the commercial unit of electrical energy?

A boy records that 4000 joule of work is required to transfer 10 coulomb of charge between two points of a resistor of 50 Ω. The current passing through it is

A fuse wire repeatedly gets burnt when used with a good heater. It is advised to use a fuse wire of

Three resistors of 1 Ω, 2 ft and 3 Ω are connected in parallel. The combined resistance of the three resistors should be

Which of the following gases are filled in electric bulbs?

Electric power is inversely proportional to

An electric bulb is rated 220 V and 100 W. When it is operated on 110 V, the power consumed will be: