102 + Interview Questions in ELECTRIC CIRCUITS IN GENERAL AWARENESS Page 1 InterviewSolution

1.	Give two differences between the electric resistance and electric specific resistance of a material.
Answer» Two differences between resistance and sp. resistance. Resistance : 1. S.I. unit is ohm (Ω) 2. It is measured as ratio of pot. difference at the ends of a conductor to the current flowing through the conductor. Resistivity or sp. Resistance : S.I. unit [Ω-m] ohm. metre. It is measured as the resistance offered by a conductor of unit length and unit area of cross-section.

1.

Give two differences between the electric resistance and electric specific resistance of a material.

Answer»

Two differences between resistance and sp. resistance.

Resistance :

1. S.I. unit is ohm (Ω)

2. It is measured as ratio of pot. difference at the ends of a conductor to the current flowing through the conductor.

Resistivity or sp. Resistance :

S.I. unit [Ω-m] ohm. metre. It is measured as the resistance offered by a conductor of unit length and unit area of cross-section.

Discussion

2.	State two multiples and two submultiples of the unit of electric potential and electric current.
Answer» Multiple units of : Electric potential is 1. ( Kv ) kilovolt = 10³V 2. Megavolt (Mv) = 10⁶V Electric current : 1. KA (kilo-ampere) = 1000A 2. MA (Mega-ampere) = 10⁶ Sub multiple units of: Electric potential: 1. mV millivolt = 10^-3V 2. µv = microvolt = 10^-6V Electric current : 1. mA = milliampere = 10^-3A 2. µA = micro-ampere = 10^-6A

2.

State two multiples and two submultiples of the unit of electric potential and electric current.

Answer»

Multiple units of :

Electric potential is

1. ( Kv ) kilovolt = 10³V

2. Megavolt (Mv) = 10⁶V

Electric current :

1. KA (kilo-ampere) = 1000A

2. MA (Mega-ampere) = 10⁶

Sub multiple units of:

Electric potential:

1. mV millivolt = 10^-3V

2. µv = microvolt = 10^-6V

Electric current :

1. mA = milliampere = 10^-3A

2. µA = micro-ampere = 10^-6A

Discussion

3.	which of element use to make bulb?
Answer» The bulb consists of a filament that gives light and two terminals.

Discussion

4.	Do not connect the two __________of a cell with a single wire.
Answer» Do not connect the two terminals of a cell with a single wire.

Discussion

5.	Connect a circuit on a wooden plank or on a thermocol sheet as shown in Figure. Insert two drawing pins at A and B. Insert a safety pin in between A and B. such that one end of the pin is completely in contact with B and the other end is left free. Now observe the bulb.What do you notice?What happens?Why doesn’t the bulb glow when the safety pin is left free at one end?
Answer» The bulb does not glow. Now touch the safety pin to pin A and observe the bulb again. The bulb glows. In this activity, the safety pin is used to close /open the circuit. When the safety pin is left free at one end, the circuit is open. So the bulb doesn’t glow.

Discussion

6.	Connect circuits as shown in the following figure. Write your observation in each case.
Answer» a) The bulb does not glow as the +ve terminals of the two cells are directly connected. b) The bulb glows as the cells are connected correctly. c) The bulb glows and gives dim light as only one cell is connected. d) The bulb glows brilliantly as the three cells are connected in series and more current flows in the bulb.

6.

Connect circuits as shown in the following figure. Write your observation in each case.

Answer»

a) The bulb does not glow as the +ve terminals of the two cells are directly connected.

b) The bulb glows as the cells are connected correctly.

c) The bulb glows and gives dim light as only one cell is connected.

d) The bulb glows brilliantly as the three cells are connected in series and more current flows in the bulb.

Discussion

7.	What is current?
Answer» The flow of electricity in a circuit is called current.

Discussion

8.	What is filament?
Answer» The part of the bulb that glows is the filament, which is a thin spring-like wire attached to the two metal wires inside the glass bulb.

Discussion

9.	Do not connect the two terminals of a cell with a single wire. Give reason.
Answer» 1. We should never connect the two terminals of a cell with a single wire. 2. If we do so, the chemicals in the cell get used up very fast and the cell stops working.

Discussion

10.	To prevent electric shock, electric wires cover with A) Plastic B) Cotton C) Iron D) Cloth
Answer» Correct option is A) Plastic

Discussion

11.	Identify the wrong part in figure1) Glass chamber2) Filament3) Metal capA) Glass chamber B) Filament C) Metal cap D) None of these
Answer» Correct option is C) Metal cap

Discussion

12.	The metal used in making filaments of present-day bulbs is A) Iron B) Copper C) Tungsten D) Cotton
Answer» The correct answer is C) Tungsten.

Discussion

13.	Match the following:Group – AGroup – B1) Cell A) Gives light2) Filament B) Conductor3) SwitchC) Insulator4) Copper wireD) open/close circuit5) Rubber coat E) Source of electrical energy
Answer» 1) E 2) A 3) D 4) B 5) C

13.

Match the following:Group – AGroup – B1) Cell A) Gives light2) Filament B) Conductor3) SwitchC) Insulator4) Copper wireD) open/close circuit5) Rubber coat E) Source of electrical energy

Answer»

1) E

2) A

3) D

4) B

5) C

Discussion

14.	In a bulb the part which gives us light is A) Metal Base B) Glass Chamber C) Filament D) Terminals
Answer» The correct answer is C) Filament.

Discussion

15.	Why are the handles of players and screwdrivers are covered with plastic and rubber?
Answer» Rubber is a bad conductor of electricity. It does not allow current to flow through it. Hence, handle of tools such as screw drivers pliers etc. which are used by electrician for repair work usually have plastic or rubber cover on them, this protects them from electric shocks.

Discussion

16.

Classify the following into conductors and insulators: Water, Plastic pen, Pencil lead, Dry cotton cloth, Wet cotton cloth, Dry wood, Wet wood.

Answer»

S.No.	Conductors	S.No.	Insulators
1	Pencil lead	4	Water
2	Wet cotton cloth	5	Plastic pen
3	Wet wood	6	Dry cotton cloth
		7	Dry wood

Discussion

17.	The central part of an electrical cell consists of A) Copper rod B) Zinc rod C) Carbon rod D) Iron rod
Answer» Correct option is C) Carbon rod

Discussion

18.	The signs of terminals of a cell are A) +, + B) +, – C) -, – D) +, ×
Answer» Correct option is B) +, –

Discussion

19.	Edison used …………. as the first filament. A) cotton B) wood C) platinum wire D) bamboo fiber
Answer» Correct option is C) platinum wire

Discussion

20.	Which is an example for a conductor? A) copper B) wood C) plastic D) rubber
Answer» Correct option is A) copper

Discussion

21.	Bulb : Glass :: Filament : ……….. A) Tungsten B) Iron C) Copper D) Aluminium
Answer» Correct option is A) Tungsten

Discussion

22.	The filament is made up of A) Copper B) IronC) Tungsten D) Aluminium
Answer» Correct option is C) Tungsten

Discussion

23.	Electric non-conductor is A) Copper B) Aluminium C) IronD) Rubber
Answer» Correct option is D) Rubber

Discussion

24.	Is our body insulator or conductor?
Answer» Our body is a good conductor of electricity.

Discussion

25.	Which of the following is used to make electric wires?(a) wood(b) copper(c) plastic(d) thread
Answer» Copper is used to make electric wires.

Discussion

26.	Make a list of the places where we use an electric cell.
Answer» In the following appliances we use electric cell, e.g., 1. radio 2. electric torch 3. calculator 4. remote controls of TV 5. watches 6. Mobile phone 7. Automatic toys of kids.

26.

Make a list of the places where we use an electric cell.

Answer»

In the following appliances we use electric cell, e.g.,

1. radio

2. electric torch

3. calculator

4. remote controls of TV

5. watches

6. Mobile phone

7. Automatic toys of kids.

Discussion

27.	How a switch works?
Answer» A switch close and open the circuit, When switch is on, then current flows in the circuit and when switch is off, then circuit is open and current does not flow.

Discussion

28.	Does generator produce electricity?
Answer» Yes, a generator can generate electricity

Discussion

29.	Why we use switch in each appliance in home?
Answer» To on and off the appliances.

Discussion

30.	What is the principle of meter bridge?
Answer» Meter bridge is based on the principle of Wheatstone bridge.

Discussion

31.	Temperature coefficient of resistance of potentiometer wire should be:(a) High(b) Low(c) Negligible(d) Infinite
Answer» (c) Negligible The specific resistance and the coefficient of linear expansion of potentiometer wire must be negligible.

Discussion

32.	Cell of emf e is balanced at length L in potentiometer experiment. Now other cell having emf e connects parallel to the first cell. Now the new balancing length will be:(a) 2L(b) L(c) \(\frac{L}{2}\)(d) \(\frac{L}{4}\)
Answer» (b) L In parallel combination there will be no effect on potential difference. So there will be no effect on balance length.

Discussion

33.	Write down the definition of the potential gradient.
Answer» Potential drop per unit length of the wire of potentiometer is known as potential gradient of potentiometer.

Discussion

34.	Give the definition of Cell?
Answer» Cell: Cell is the source of energy. An electric cell is a sort of container that produces electricity from the chemical stored inside it.

Discussion

35.	Mention two factors which determine the internal resistance of a cell.
Answer» The internal resistance of a cell depends on 1. Surface area of electrodes and 2. distance between the electrodes.

35.

Mention two factors which determine the internal resistance of a cell.

Answer»

The internal resistance of a cell depends on

1. Surface area of electrodes and

2. distance between the electrodes.

Discussion

36.	What is the difference between emf and terminal voltage of a cell?
Answer» Difference between e.m.f. and terminal voltage : Terminal voltage : When current is drawn from a cell i.e. the cell is in a closed circuit, the potential differences between the electrodes (terminals) of a cell is called terminal voltage, e.m.f. : “when no current is drawn from a cell i.e. when the cell is in open circuit, the pot. difference between the terminals of the cell is called electromotive force, (e.m.f.).

36.

What is the difference between emf and terminal voltage of a cell?

Answer»

Difference between e.m.f. and terminal voltage :

Terminal voltage : When current is drawn from a cell i.e. the cell is in a closed circuit, the potential differences between the electrodes (terminals) of a cell is called terminal voltage,

e.m.f. : “when no current is drawn from a cell i.e. when the cell is in open circuit, the pot. difference between the terminals of the cell is called electromotive force, (e.m.f.).

Discussion

37.	State the factors on which internal resistance of a cell depends.
Answer» Factors effecting the internal resistance of a cell : 1. Surface area of electrodes larger surface area, lesser is the internal resistance. 2. Distance between electrodes : more the distance, more is the internal resistance. 3. Temp, of electrolyte r α 1/T 4. Higher the concentration of electrolyte greater is internal resistance.

37.

State the factors on which internal resistance of a cell depends.

Answer»

Factors effecting the internal resistance of a cell :

1. Surface area of electrodes larger surface area, lesser is the internal resistance.

2. Distance between electrodes : more the distance, more is the internal resistance.

3. Temp, of electrolyte r α 1/T

4. Higher the concentration of electrolyte greater is internal resistance.

Discussion

38.	A substance has nearly zero resistance at a temperature of 1K. What is such a substance called? State any two factors which affect the resistance of a metallic wire
Answer» Superconductor The resistance of a metallic wire is affected by (a) Its area of cross-section. Ra% (b) Length of conductor R ∝ 1/a

38.

A substance has nearly zero resistance at a temperature of 1K. What is such a substance called? State any two factors which affect the resistance of a metallic wire

Answer»

Superconductor

The resistance of a metallic wire is affected by

(a) Its area of cross-section. Ra%

(b) Length of conductor R ∝ 1/a

Discussion

39.	State the laws of resistance.
Answer» Laws of resistance : 1. Resistance of a conductor is directly proportional to its length R α 1 2. Resistance of a conductor is Inversely proportional to its area of cross-section R α 1/a 3. Resistance of a conductor depend upon its nature i.e. copper has less resistance than iron. 4. Resistance of a conductor increases with increase in temperature i.e. resistance of filament of a bulb is more when lighted as compared to when it is not lighted.

39.

State the laws of resistance.

Answer»

Laws of resistance :

1. Resistance of a conductor is directly proportional to its length R α 1

2. Resistance of a conductor is Inversely proportional to its area of cross-section R α 1/a

3. Resistance of a conductor depend upon its nature i.e. copper has less resistance than iron.

4. Resistance of a conductor increases with increase in temperature i.e. resistance of filament of a bulb is more when lighted as compared to when it is not lighted.

Discussion

40.	What is a superconductor? Name two materials and the temperature at which they become superconductors.
Answer» SUPER CONDUCTOR : “The substances which lose resistance when they are cooled to very low temperature (nearly absolute zero) are called super conductors, e.g. mercury at 4.12k, LEAD. TIN, VANADIUM etc. and this phenomenon is called SUPER CONDUCTIVITY. The temperature at which they become super-conductors is called CRITICAL TEMPERATURE.

Discussion

41.	The materials required to make a simple circuit is A) Bulb, wires B) Bulb, switch, cells C) Switch, cells, wires D) Bulb, switch, cell, wires
Answer» Correct option is D) Bulb, switch, cell, wires

Discussion

42.	A complete electric circuit is called ……………. electric circuit. A) Open B) Closed C) CompleteD) None of these
Answer» Correct option is B) Closed

Discussion

43.	Define electric potential. State its practical unit and define it.
Answer» Electric Potential : “Is the electrical state of a conductor which determines the direction of flow of charge when two conductors are either in contact or joined by a metallic wire.” Or ELECTRIC POTENTIAL “at a point is the work done in moving unit positive charge from infinity to that point in an electric field. S.I. unit is volt. VOLT : “If work done in moving 1 coulomb of charge from one point to other is 1 joule, the potential difference between two points is said to be 1 volt.”

43.

Define electric potential. State its practical unit and define it.

Answer»

Electric Potential : “Is the electrical state of a conductor which determines the direction of flow of charge when two conductors are either in contact or joined by a metallic wire.”

Or

ELECTRIC POTENTIAL “at a point is the work done in moving unit positive charge from infinity to that point in an electric field. S.I. unit is volt.

VOLT : “If work done in moving 1 coulomb of charge from one point to other is 1 joule, the potential difference between two points is said to be 1 volt.”

Discussion

44.	In the given circuit which acts as switch?A) Bulb B) CellC) Safety pin D) Wires
Answer» Correct option is C) Safety pin

Discussion

45.	When circuit is open current will A) flow B) not flow C) increase D) Decrease
Answer» Correct option is B) not flow

Discussion

46.	Define quantity of charge. States its practical unit and define it
Answer» Quality of charge is “The number of charges (electrons) which drift from a higher to a lower potential is called quantity of charge.” Particle unit of charge is coulomb. Coulomb: “Flow of 6.25 × 10¹⁸ electrons through a conductor constitute 1 coulomb.” Or “Charge carried by 6.25 × 10¹⁸ electrons is called 1 coulomb.”

46.

Define quantity of charge. States its practical unit and define it

Answer»

Quality of charge is “The number of charges (electrons) which drift from a higher to a lower potential is called quantity of charge.” Particle unit of charge is coulomb.

Coulomb: “Flow of 6.25 × 10¹⁸ electrons through a conductor constitute 1 coulomb.”

Or

“Charge carried by 6.25 × 10¹⁸ electrons is called 1 coulomb.”

Discussion

47.	Identify the part ‘X’ symbol in the given figureA) Metal cap B) Filament C) Terminals D) Glass
Answer» Correct option is B) Filament

Discussion

48.	Two conductors A and B have 500 and 100 units of . negative charge when the conductors are connected by an electric wire the conventional current flows from : (a) A to B (b) B to A (c) Current does not flow (d) none of these
Answer» The conventional current flows from B to A.

Discussion

49.	Shortline on battery symbol represents the A) Positive terminal B) Negative terminal C) ResistanceD) None of these
Answer» Correct option is B) Negative terminal

Discussion

50.	Cell is A) On / Off B) Connector C) Supplies current D) Filament
Answer» Correct option is C) Supplies current

Discussion

Explore topic-wise InterviewSolutions in .

Give two differences between the electric resistance and electric specific resistance of a material.

State two multiples and two submultiples of the unit of electric potential and electric current.

which of element use to make bulb?

Do not connect the two __________of a cell with a single wire.

Connect circuits as shown in the following figure. Write your observation in each case.

What is current?

What is filament?

Do not connect the two terminals of a cell with a single wire. Give reason.

To prevent electric shock, electric wires cover with A) Plastic B) Cotton C) Iron D) Cloth

Identify the wrong part in figure1) Glass chamber2) Filament3) Metal capA) Glass chamber B) Filament C) Metal cap D) None of these

The metal used in making filaments of present-day bulbs is A) Iron B) Copper C) Tungsten D) Cotton

Match the following:Group – AGroup – B1) Cell A) Gives light2) Filament B) Conductor3) SwitchC) Insulator4) Copper wireD) open/close circuit5) Rubber coat E) Source of electrical energy

In a bulb the part which gives us light is A) Metal Base B) Glass Chamber C) Filament D) Terminals

Why are the handles of players and screwdrivers are covered with plastic and rubber?

Classify the following into conductors and insulators: Water, Plastic pen, Pencil lead, Dry cotton cloth, Wet cotton cloth, Dry wood, Wet wood.

The central part of an electrical cell consists of A) Copper rod B) Zinc rod C) Carbon rod D) Iron rod

The signs of terminals of a cell are A) +, + B) +, – C) -, – D) +, ×

Edison used …………. as the first filament. A) cotton B) wood C) platinum wire D) bamboo fiber

Which is an example for a conductor? A) copper B) wood C) plastic D) rubber

Bulb : Glass :: Filament : ……….. A) Tungsten B) Iron C) Copper D) Aluminium

The filament is made up of A) Copper B) IronC) Tungsten D) Aluminium

Electric non-conductor is A) Copper B) Aluminium C) IronD) Rubber

Is our body insulator or conductor?

Which of the following is used to make electric wires?(a) wood(b) copper(c) plastic(d) thread

Make a list of the places where we use an electric cell.

How a switch works?

Does generator produce electricity?

Why we use switch in each appliance in home?

What is the principle of meter bridge?

Temperature coefficient of resistance of potentiometer wire should be:(a) High(b) Low(c) Negligible(d) Infinite

Cell of emf e is balanced at length L in potentiometer experiment. Now other cell having emf e connects parallel to the first cell. Now the new balancing length will be:(a) 2L(b) L(c) \(\frac{L}{2}\)(d) \(\frac{L}{4}\)

Write down the definition of the potential gradient.

Give the definition of Cell?

Mention two factors which determine the internal resistance of a cell.

What is the difference between emf and terminal voltage of a cell?

State the factors on which internal resistance of a cell depends.

A substance has nearly zero resistance at a temperature of 1K. What is such a substance called? State any two factors which affect the resistance of a metallic wire

State the laws of resistance.

What is a superconductor? Name two materials and the temperature at which they become superconductors.

The materials required to make a simple circuit is A) Bulb, wires B) Bulb, switch, cells C) Switch, cells, wires D) Bulb, switch, cell, wires

A complete electric circuit is called ……………. electric circuit. A) Open B) Closed C) CompleteD) None of these

Define electric potential. State its practical unit and define it.

In the given circuit which acts as switch?A) Bulb B) CellC) Safety pin D) Wires

When circuit is open current will A) flow B) not flow C) increase D) Decrease

Define quantity of charge. States its practical unit and define it

Identify the part ‘X’ symbol in the given figureA) Metal cap B) Filament C) Terminals D) Glass

Two conductors A and B have 500 and 100 units of . negative charge when the conductors are connected by an electric wire the conventional current flows from : (a) A to B (b) B to A (c) Current does not flow (d) none of these

Shortline on battery symbol represents the A) Positive terminal B) Negative terminal C) ResistanceD) None of these

Cell is A) On / Off B) Connector C) Supplies current D) Filament