Ch-12 Electricity

Which of the following represents voltage?
a. work done/charge X current
b. work done/charge

Unit of electric power may also be expressed as
(a) volt ampere
(b) kilowatt hour
(c) watt second
(d) Joule second

Electrical resistivity of a given metallic wire depends upon
(a) its length
(b) its thickness
(c) its shape
(d) nature of the material

The unit of e.m.f.(Electromotive Force) of a cell is
(a) dyne
(b) volt
(c) ampere
(d) joule

Kilowatt hour is the unit of
(a) power
(b) energy
(c) impulse
(d) force

Materials which allow larger currents to flow through them are called
(a) insulators
(b) conductors
(c) semiconductors
(d) alloys

Conventionally, the direction of the current is taken as
(a) the direction of flow of negative charge
(b) the direction of flow of atoms
(c) the direction of flow of molecules
(d) the direction of flow of positive charge

The unit of specific resistance is
(a) ohm
(b) ohm
(c) ohm-metre
(d) ohm per metre

The variable resistance is called
(a) resistor
(b) rheostat
(c) open switch
(d) none of these

The SI unit of resistance is
(a) ohm m
(b) ohm m1
(c) ohm
(d) (ohm)-1

An electric iron draws a current 4 A when connected to a 220 V mains. Its resistance must be
(a) 1000 Ω
(b) 55 Ω
(c) 44 Ω
(d) None of these

The element used almost exclusively for filaments of incandescent lamps
(a) copper
(b) gold
(c) silver
(d) tungsten

1. …………… measures the potential differences between two points of the circuit

2. Ammeter is used to measure the magnitude of …………… through any wire of a circuit.

3. Electric current flows in the circuit from …………… terminal of cell to the …………… terminal of cell.

4. Copper and aluminium are used for electric transmission lines because both posses …………… resistivity.

5. The rate at which electric energy is consumed or dissipated is called ……………

Presence of chemically inactive gases like argon and …………… prolong the life of the filament.