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Current Electricity 9th Class MCQ

 

Chapter No.3

 Current Electricity MCQ
9th Class
Maharashtra State Board
Multiple Choice Questions

Current Electricity MCQ 9th Class


1

The S.I unit of power is?

A

Henry

B

Coulomb

C

Watt

D

Watt-hour

ANS

Watt

 

2

Electric pressure is also called?

A

Resistance

B

Power

C

Voltage

D

Energy

ANS

Voltage

 

3

Out of the following which is not a poor conductor?

A

Cast iron

B

Copper

C

Carbon

D

Tungsten

ANS

Copper

 

4

The substances which have a large number of free electrons and offer a low resistance are called?

A

Insulators

B

Inductors

C

Semi-conductors

D

Conductors

ANS

Conductors

 

5

Out of the following which is an insulating material?

A

Copper

B

Gold

C

Sliver

D

Paper

ANS

Paper

 

6

Conductance is reciprocal of?

A

Resistance

B

Inductance

C

Reluctance

D

Capacitance

ANS

Resistance

 

7

The property of a conductor due to which it passes current is called?

A

Resistance

B

Reluctance

C

Conductance

D

Inductance

ANS

Conductance

 

8

The resistance of a conductor varies inversely as?

A

Length

B

Area of cross-section

C

Temperature

D

Resistivity

ANS

Area of cross-section

 

9

With rise in temperature the resistance of pure metal?

A

Increases

B

Decreases

C

First increases and then decreases

D

Remains constant

ANS

Increases

 

10

With rise in temperature the resistance of semi-conductors?

A

Decreases

B

Increases

C

First increases and then decreases

D

Remains constant

ANS

Decreases

  

11

Three resistances of 10 ohms, 15 ohms and 30 ohms are connected in parallel. The total resistance of the combination is?

A

50 ohms

B

10 ohms

C

15 ohms

D

55 ohms

ANS

50 ohms

 

12

An instrument which detects electric current is known as?

A

Voltmeter

B

Rheostat

C

Wattmeter

D

Galvanometer

ANS

Galvanometer

 

13

In a circuit a 33Q resistor carries a current of 2A. The voltage a cross the resistor is?

A

33 V

B

66 V

C

80 V

D

132 V

ANS

66 V

 

14

A light bulb draws 300 mA when the voltage across it is 240 V. The resistance of the light bulb is?

A

400 Q

B

600 Q

C

800 Q

D

1000 Q

ANS

800 Q

 

15

The resistance of a parallel circuit consisting of two branches is 120 ohms. It the resistance of one branch is 18 ohms, what is the resistance of the others?

A

18 Q

B

36 Q

C

48 Q

D

64 Q

ANS

36 Q

  

16

Which of the following material has nearly zero temperature co-efficient of resistance?

A

Magnanin

B

Porcelain

C

Carbon

D

Copper

ANS

Magnanin

 

17

You have to replace 1500 Q resistor in ratio. You have no 1500 Q resistor but have several 1000 Q ones which you would connect?

A

Two in parallel

B

Two in parallel and one in series

C

Three in parallel

D

Three in series

ANS

Two in parallel and one in series

 

18

Two resistors are said to be connected in series when?

A

Same current passes in turn through both

B

Both carry the same value of current

C

Total current equals the sum of branch currents

D

Sum of IR drops equals the applied e.m.f

ANS

Same current passes in turn through both

 

19

Which of the following statement is true both for a parallel D.C circuit?

A

Elements have individual currents

B

Currents are additive

C

Voltages are additive

D

Power are additive

ANS

Power are additive

 

20

Which of the following materials has a negative temperature co-efficient of resistance?

A

Copper

B

Aluminum

C

Carbon

D

Brass

ANS

Carbon

  

21

Ohm’s law is not applicable to?

A

Vacuum tubes

B

Carbon resistors

C

High voltage circuits

D

Circuits with low current densities

ANS

Vacuum tubes

 

22

For which of the following ‘ampere second’ could be the unit?

A

Reluctance

B

Charge

C

Power

D

Energy

ANS

Charge

 

23

Which is the best conductor of electricity?

A

Iron

B

Silver

C

Copper

D

Carbon

ANS

Silver

 

24

Which one of the following does not have negative temperature co-efficient?

A

Aluminum

B

Paper

C

Rubber

D

Mica

ANS

Aluminum

 

25

Varistors are?

A

Insulators

B

Non-linear resistor

C

Carbon resistors

D

Resistors with zero temperature

ANS

Non-linear resistor

  

26

The rating of a fuse wire is always expressed in?

A

Ampere – hours

B

Ampere – volts

C

Kwh

D

Amperes

ANS

Amperes

 

27

The filament of an electric bulb is made of?

A

Carbon

B

Aluminum

C

Tungsten

D

Nickel

ANS

Tungsten

 

28

A 3 Q resistor having 2 A current will dissipate the power of?

A

2 watts

B

4 watts

C

6 watts

D

8 watts

ANS

6 watts

 

29

The resistance of a few meters of wire conductor in closed electrical circuit is?

A

Practically zero

B

Low

C

High

D

Very heigh

ANS

Practically zero

 

30

A caused switch has a resistance of?

A

Zero

B

About 50 ohms

C

About 500 ohms

D

Infinity

ANS

Zero

  

31

The hot resistance of the bulb’s filament is higher than its could resistance because the temperature co-efficient of the filament is?

A

Zero

B

Negative

C

Positive

D

About 2 ohms per degree

ANS

Positive

 

32

The thickness of insulation provided on the conductor depends on?

A

The magnitude of voltage on the conductor

B

The magnitude of current flowing through it

C

Both A and B

D

None of the above

ANS

The magnitude of voltage on the conductor

 

33

Which of the following quantities remain the same in all parts of a series circuit?

A

Voltage

B

Current

C

Power

D

Resistance

ANS

Current

 

34

A 40w bulb is connected in series with a room heater. If now 40 w bulb is replaced by 100w bulb, the heater output will?

A

Decreases

B

Increases

C

Remain same

D

Heater will burn out

ANS

Increases

 

35

An electric filament bulb can be worked from?

A

D.C supply only

B

A.C supply only

C

Battery supply only

D

All above

ANS

All above

  

36

Electric current passing through the circuit produces?

A

Magnetic effect

B

Luminous effect

C

Thermal effect

D

Chemical effect

ANS

Thermal effect

 

37

If the efficiency of a machine is to be high, what should be low?

A

Input power

B

Losses

C

True component of power

D

Kwh consumed

ANS

Losses

 

38

A glass rod when rubbed with silk cloth is changed because?

A

It tubes in proton

B

Its atoms are removed

C

It gives away electrons

D

It gives away positive charge

ANS

It gives away electrons

 

39

Whether circuit may be AC on DC one, following is most effective in reducing the magnitude of the current?

A

Reactor

B

Capacitor

C

Inductor

D

Resistor

ANS

Resistor

 

40

When electric current passes through a bucket full of water, lot of bubbling is observed. This suggests that the type of supply is?

A

A.C

B

D.C

C

Any of above two

D

None of the above

ANS

D.C

  

 

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