Unit 17: Electric Circuits

1

Which color is usually used for the live wire?

A Green B Blue C Brown D Yellow

2

If voltage across a resistor is doubled, the current will:

A Remain same B Become half C Double D Become zero

3

The material used for making fuse wire should have:

A High melting point B Low melting point C High resistance D Low resistance

4

The purpose of a circuit diagram is to:

A Decorate the circuit B Show actual size C Represent components symbolically D Measure current

5

Electric shock occurs due to:

A Low voltage B High resistance C Flow of current through body D Static charge

6

The purpose of earthing is to:

A Increase voltage B Reduce current C Prevent electric shock D Save energy

7

The main source of electricity in homes is:

A Battery B Generator C Power station D Solar cell only

8

Which material is commonly used to make a fixed resistor?

A Copper B Carbon C Silver D Gold

9

Which safety device automatically breaks the circuit during overload?

A Switch B MCB C Plug D Socket

10

Which of the following is a safety precaution?

A Using bare wires B Overloading sockets C Proper earthing D Wet hands operation

11

Which graph represents Ohm’s law?

A Current vs Resistance B Voltage vs Resistance C Current vs Voltage D Power vs Voltage

12

Which factor increases electric power?

A Decrease in voltage B Decrease in current C Increase in voltage D Increase in resistance

13

In a series combination of resistors, the total resistance is:

A Less than the smallest resistance B Equal to one resistor C Sum of all resistances D Product of resistances

14

The SI unit of electric power is:

A Joule B Ampere C Watt D Volt

15

The electromotive force (EMF) of a cell is measured in:

A Ampere B Ohm C Volt D Watt

16

One kilowatt-hour is equal to:

A 1000 joules B 3600 joules C 3.6 × 10^6 joules D 3.6 × 10^3 joules

17

Which symbol represents a cell in a circuit diagram?

A Zigzag line B Long and short parallel lines C Circle with a cross D Straight line

18

A fuse is used in a circuit to:

A Increase current B Measure voltage C Prevent overheating D Store charge

19

The SI unit of electric current is:

A Volt B Ohm C Ampere D Watt

20

Which component is used to control the flow of electric current in a circuit?

A Switch B Resistor C Battery D Bulb

21

Which of the following reduces the risk of electric shock?

A Wet floor B Insulated wires C Broken plug D Overloading

22

Which of the following is NOT a circuit element?

A Resistor B Cell C Wire D Magnet

23

Which device is used to measure electric current?

A Voltmeter B Galvanometer C Ammeter D Ohmmeter

24

Electric power can be calculated using the formula:

A P = IR B P = V/I C P = VI D P = R/I

25

When cells are connected in series, the total EMF is:

A Average of EMFs B Difference of EMFs C Sum of EMFs D Product of EMFs