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Correct Answer is: (a, c)

(b) Filament

(d) Terminal

Take an electric circuit, keep the terminals unconnected in the air the bulb does not glow ads air is an insulator and does not allow the current to flow through it.

Electric cell : Alessandro Volta 

Electric bulb : Thomas Alva Edison

Correct answer is  (c) cell

1. If one device is stopped or failed to work, all other devices will also stop. 

2. If one device is switched on the other devices will also works.

A conductor is that which easily allows the passage of current through it 

Ex: Aluminium or copper An insulator is that which does not allow the passage of current through it 

Ex: Rubber. Plastic

1. Television 

2. Computer 

3. Laptop

4. Mobile Phones 

5. Fridge 

6. Heater 

7. Air conditioner 

8. Microwave oven

9. Inverter 

10. Washing machine with drier.

Conductors:

The rate of flow of electric charges in a circuit is called electric current. The materials which allow electric charges to pass through them are called conductors. 

Examples: Copper, iron, aluminum, impure water, earth etc.,

Iniulaton (Non-Conductors): The materials which do not allow electric charges to pass through them are called insulators or non- conductors. 

Examples: plastic, glass, wood, rubber, china clay, ebonite etc.

MCB is better, when compared to electric fuse. There is no need to change it often. But wire in electric fuse has to be changed whenever it melts.

Conductors: 

Materials which allow the electric current to pass through them are called conductors. 

Example: All metals, Salt water.

Insulators: 

Materials do not allow the current to pass through them are called insulators. 

Example: Dry wood, plastics, rubber, glass.

Electricity voltage is supplied to our houses at 220 volt.

The correct option is C) Electromagnets.

In the house hold electric circuit the appliances are connected in parallel and each appliance has an independent path for current and work at the same voltage. Hence, if one bulb in a room is fused, the other bulbs keep glowing.

Solution :

 Conductor :- mercury, aluminum, iron, metal coin 

Resistor :- manganin, nichrome 

Insulator :- rubber, polythene, wood, bakelite, paper, thermocol 

The correct option is A) Nichrome.

The correct option is B) Tungsten.

Solution : 

Conductor:- Silver, Copper, Aluminum, Nichrome, Graphite, Mercury, Manganin Insulators:- Sulphur, Cotton, Air, Paper, Porcelain, Mica, Bakelite, Polythene

Electromagnet is used in ELECTRICAL APPLIANCES like ELECTRIC BELL, RADIO, T.V., FAN and MOTORS etc.

The magnetic field of an electromagnet (I or U-shaped) can be increased by the following two ways : 

1. By increasing the number of turns of winding in the solenoid. 

2. By increasing the current through the solenoid.

Electromagnets are used in cars, speakers, electric motors, electric cells, telephone receivers and television

Uses of electromagnet — 

1. In electrical appliances such as electric bell, fan etc. 

2. In lifting heavy loads of iron scrap. 

3. To remove tiny particles of iron from the wound. 

4. In loading furnaces with iron. 

5. In separation of magnetic substances from the non-magnetic substances.

Resistance R = 10 Ω 

Let l be the length of the wire R ∝ 1 

When the length is increased to three times, 

l’ = 3l 

∴ New Resistance

R’ ∝ l’ ∝ 3l

∴ \(\frac{R}{R'} = \frac{l}{3l} = \frac{1}{3}\)

∴ R' = 3R

New resistance = 3 times the original resistance.

(a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.

The resistance of a conductor is said to be one ohm if a current of one ampere flows through it when a potential difference of one volt is maintained across its ends.

Ohm = \(\frac{1 volt}{1 ampere}\)

(c) If the assertion is true, but the reason is false.

(i) The unit of resistance is ohm. 

(ii) The unit of resistivity is ohm meter.

The resistance of a conductor can be defined as the ratio between the potential difference across the ends of the conductor and the current flowing through it. Conductance: It is defined as the reciprocal of its resistance (R). Hence, the conductance ‘G’ of a conductor is given by

G = \(\frac{1}{R}\)

Its unit is ohm^-1 . It is also represented as ‘mho’

The electrical resistivity of a material is defined as the resistance of a conductor of unit length and unit area of cross section. Its unit is ohm metre.

Correct answer is (b) constant.

 Mathematically, resistivity of the conducting material is given by 

ρ = R x A/J 

If l = 1 m, A = 1 m², then ρ = R

Hence, the resistivity of the material is defined as the resistance offered by a metallic wire having a unit length and a unit area of cross-section. Since unit length and unit area of cross-section forms a cube, the specific resistance or resistivity can also be defined as the resistance offered by a cube of a material of side 1 m when current flows perpendicularly through the opposite faces. In 

SI system, its units is

Unit of ρ = Unit of R X Unit of area of cross -Section/Unit of length of Conductor

 = Ω x m²/m = Ωm

The resistivity of a metallic wire increases with increase in temperature.

Resistivity: It is defined as the resistance offered by a conductor having unit length and unit cross-sectional area. It is denoted by ρ (rho). 

ρ = \(\frac{R\,\times\,A}l\)

The SI unit of resistivity ρ in Ωm.

Factors on which the resistance of a cylindrical conductor depends:

(i) Area of a cross-section of the conductor.

(ii) Nature of the material.

SI unit of resistivity is ohm-m.

Correct answer is (b) 1.5 × 10^-6 Ωm

(i) No, electricity theft is not good.
(ii) Proper connection, billing, safety measure can save both property and life which is more precious. People should become responsible citizens and should not be involved in any unlawful and risky events like electric theft, etc.

Correct answer is (b) same