MCQ Questions for Class 10 Physics Electricity Quiz 1

When resistors with different resistances are connected in series, which of the following must be the same for each resistor? Choose all correct answers

0%
potential difference
0%
current
0%
power delivered
0%
charge entering each resistor in a given time interval
0%
none of those answers

$\displaystyle \frac { Charge }{ Time } =....$

0%
Voltage
0%
Current
0%
Potential
0%
Work done

Explanation

Electric current is defined as the rate of flow of electric charge.

Current

$I = \dfrac{q}{t}$ where

$q$ is the charge flowing and

$t$ is the time

The rating of an electrical appliance is

$60 W$ ,

$220 V$ . What is the safe limit of current in it, while in use ?

0%
$0.20 A$
0%
$0.27 A$
0%
$0.50 A$
0%
$1.2 A$

Explanation

Given :

$P =60$ W

$V = 220$ Volts

Safe limit of current

$I_{max} =\dfrac{P}{V} =\dfrac{60}{220} =0.27$ A

When does two elements are said to be in series?

0%
When same current physically flows through both elements
0%
When different current physically flows through both elements
0%
When no current physically flows through both elements
0%
None of these

What is the power produced by an appliance marked "

$240 V$ ,

$2 A"?$

0%
$8.3\ W$
0%
$60\ W$
0%
$120\ W$
0%
$480\ W$

Explanation

Relation between power

$(P)$ , voltage

$(v)$ and current

$(I)$ -

$P = VI$

Given,

$V = 240\ V$

$I = 2\ A$

$\Rightarrow P = 240 \times 2$

$\Rightarrow P = 480\ W$

Substances that do not allow free flow of charge through them are called __________.

0%
Insulators
0%
Conductors
0%
Both A and B
0%
None of these

A rod of a certain metal is

$1.0\ m$ long and

$0.6\ cm$ in diameter. Its resistance is

$3.0\times 10^{-3}\Omega$ . Another disc made of the same metal is

$2.0\ cm$ in diameter and

$1.0\ mm$ thick. What is the resistance between the round faces of the disc?

0%
$1.35\times 10^{-8}\Omega$
0%
$2.70\times 10^{-7}\Omega$
0%
$4.05\times 10^{-6}\Omega$
0%
$8.10\times 10^{-5}\Omega$

Explanation

Resistance of the material of the rod

$\rho = \dfrac {RA}{l} = \dfrac {3\times 10^{-3} \times \pi (0.3\times 10^{-2})^{2}}{1}$

$= 27\times 10^{-9} \pi \Omega m$
Resistance of disc,

$R = \dfrac {\text {Resistivity of rod}\times thickness}{\text {Area of cross-section}}$

$= 27\times 10^{-9}\pi \dfrac {10^{-3}}{\pi (1 \times 10^{-2})^{2}}$

$= 2.7\times 10^{-7}\Omega$ .

On a bulb is written 220 Volt and 60 watt. Find out the resistance of the bulb and the value of the current flowing through it.

0%
806.66 ohm 0.27 ampere
0%
500 ohm 12 ampere
0%
200 ohm 14 ampere
0%
100 ohm 11 ampere

Explanation

$P=\dfrac{V^2}{R}=VI$

Hence,

$R=\dfrac{V^2}{P}=\dfrac{220\times 220}{60}$

$\implies R=806.66\Omega$

$I=\dfrac{P}{V}=\dfrac{60}{220}$

$\implies I=0.27A$

Answer-(A)

In the circuit shown in figure, the current flowing through

$5 \, \Omega$ resistance is

0%
$0.5 \, A$
0%
$0.6 \, A$
0%
$0.9 \, A$
0%
$1.5 \, A$

Explanation

$\textbf{Step 1: Apply Kirchhoff's current law [Refer Fig.]}$

Apply Kirchhoff's current law at junction A,

$2.1 A = I_{1} + I_{2}$

$....(1)$

$\textbf{Step 2: Apply Kirchhoff's Voltage law }$

Apply KVL in the loop (in clockwise direction)

$8I_{1} + 2I_{1} - 5I_2-20I_{2} = 0$

$\Rightarrow 10I_{1} = 25 I_{2}$

$\Rightarrow I_{1} = 2.5 I_{2}$

$....(2)$

$\textbf{Step 3: Solving equations}$

Equation

$(1)$ and

$(2)\Rightarrow$

$2.1 = 2.5 I_{2} +I_2$

$\Rightarrow I_{2} = \dfrac{2.1}{3.5} = 0.6\ A$

Current through

$20\ \Omega$ and

$5\ \Omega$ will be the same i.e.

$0.6A$ as they are connected in series.

Hence, Option

$B$ is correct

$\textbf{Alternate solution:}$

In a parallel combination of resistor

$R_1$ and

$R_2$ , we know that current through

$R_2$ is given by-

$I_2=\dfrac{R_1}{R_1+R_2}I$ ,

In this case,

$R_1= 6\Omega+4\Omega= 10\Omega$ and

$R_2= 20\Omega+5\Omega=25\Omega$

$\Rightarrow I_2=\dfrac{10}{10+25}\times 2.1A = 0.6A$

This is current through

$5\Omega$ resistor.

2110313_318902_ans_a76985890eaa47dfb8f9590b5a9d9959.png

An electric iron draws a current of 15 A from a 220 V supply, What is the cost of using iron for 30 min everyday for 15 days if the cost of unit (1 unit =1 kWhr) is 2 rupees ?

0%
Rs 49.5
0%
Rs 60
0%
Rs 40
0%
Rs 10

Explanation

As we know that power(P)=v

$\times$ I
so P=15

$\times$ 220=3300 watt
cost per unit=2 rupees
therefore,

$\dfrac {3300\times2\times15\times30}{60\times1000}$ =49.5 rupees.

$24 \ V$ potential difference is applied across a parallel combination of four

$6 \ \Omega$ resistor. The current in each resistor is:

0%
$1 \ A$
0%
$4 \ A$
0%
$16 \ A$
0%
$36 \ A$

Explanation

Since the resistors are connected in parallel,the voltage across each resistor is the same ,i.e

$24 \ V$ .

Therefore, current in each resistor can now simply be calculated using the relation,

$I = \dfrac{V}{R} \implies I = \dfrac{24}{6.0} = 4.0 \ A$

Electric current is to be passed from one body to another. For this purpose the two bodies must be joined by

0%
cotton thread
0%
plastic string
0%
copper wire
0%
rubber band

In a metallic conductor, electric current is thought to be due to the movement of:

0%
ions
0%
amperes
0%
electrons
0%
protons

The flow of the electric current through a metallic conductor is:

0%
Only due to electrons
0%
Only due to +ve charges
0%
Due to both nuclei and electrons.
0%
Can not be predicted.

An electric bulb works on

$230\ V$ line and draws

$0.1\ A$ current. The resistance of the filament is:

0%
$230\ \Omega$
0%
$2300\ \Omega$
0%
$23\ \Omega$
0%
$2.3\ \Omega$

Explanation

Voltage,

$V=230\ V$

Current,

$I = 0.1\ A$

According to Ohm's law,

$V = IR$

$\Rightarrow R = \dfrac{V}{I}$

$= \dfrac{230}{0.1}$

$\Rightarrow R = 2300\ \Omega$

Which of the following option has no effect on an electric fuse wire?

0%
Its specific resistance
0%
Its radius
0%
Its colour
0%
Current flowing through it

Four identical wires each having resistance

$R$ are connected as shown in the figure. Equivalent resistance between A and B is:

0%
$\dfrac{R}{4}$
0%
$\dfrac{R}{2}$
0%
$4R$
0%
$R$

Explanation

Simplified circuit is drawn. It is the series combination of the four resistances.

$R_{AB} = 4R$

When we pay for our electricity bill, we are paying for the:

0%
charge used.
0%
current used.
0%
power used.
0%
energy used.

Which one of the following is not the unit of energy?

0%
joule
0%
newton metre
0%
kilowatt
0%
kilowatt hour

Explanation

$\textbf{Hint:}$ Use the relation between energy and power.

$\textbf{Explanation :}$

If Watt is unit of power then kilowatt is also the unit of power.
Work done = Force × Distance = Newton - metre, Therefore it is the unit of Work or Energy.
Energy = Power × time = kilowatt - hour, in fact it is the commercial unit of Energy.

The electric current passing through a metallic wire produces heating because of:

0%
collisions of conduction electrons with each other
0%
collisions of the atoms of the metal with each other
0%
the energy released in the ionisation of the atom of the metal
0%
collisions of the conduction electrons with the atoms of the metallic wire

If doubling the voltage across a resistor doubles the current through the resistor then

0%
the resistor value decreased.
0%
the resistor value increased.
0%
the resistor value did not change.
0%
it is impossible to determine the change in the resistor value.

Explanation

$R = \dfrac{V}{I}$

Now voltage =

$2V$ and current =

$2I$

So now resistance =

$\dfrac{2V}{2I}= \dfrac{V}{I}=R$

When the potential difference between two points is 1 volt and current through it is 1 A, then the resistance between the points is:

0%
$3 \, \Omega$
0%
$2 \, \Omega$
0%
$0.5 \, \Omega$
0%
$1 \, \Omega$

Explanation

Given:

Potential difference

$V=1\ volt$

Current

$I = 1\ A$

From Ohm's law,

$V = IR$

$\therefore R = \dfrac{V}{I} = \dfrac{1}{1} = 1\ ohm$

What is the relation between resistance R and resistivity

$\rho$ of a wire ?

0%
$R=\dfrac{\rho A}{l}$
0%
$R=\dfrac{\rho l}{A}$
0%
$R=\dfrac{A}{\rho l}$
0%
$R=\dfrac{l}{\rho A}$

Explanation

resistivity is a measure of the resisting power of a specified material to the flow of an electric current. So resistance is directly proportional to resistivity of material used.

$R\propto \rho$

If length is larger then electron has to travel longer so resistance is directly proportion to length.

$R\propto l$

If cross sectional area larger electron gets sufficient space for travel so resistance is inversely proportion to cross sectional area.

$R \propto \dfrac{1}{A}$

hence

$R = \rho \dfrac{l}{A}$

Electrical charge can be transferred from a charged object to another through :

0%
Vacuum
0%
Air
0%
Insulators
0%
Conductors

Name the material used for making the connection wires.

0%
tin
0%
copper
0%
lead
0%
tungsten

The commercial unit of electric energy is

$kilowatt-hour\ (kW h)$ , commonly known as:

0%
$Unit$
0%
$Faraday$
0%
$Curie$
0%
None of these

Explanation

The commercial unit of electrical energy is

$kilowatt-hour\ (kWh)$ , commonly known as

$unit$ .

$1\ kW h = 1\ unit=3.6 \times 10^6 J$ . Electricity bills are calculated in the units of energy consumed.

Fill in the blank-

An electric fuse works on the ______effect of current.

0%
heating
0%
magnetic
0%
chemical
0%
none of these

A fuse wire is generally made of

0%
tin
0%
tin-lead alloy
0%
copper
0%
either (a) or (b) above

A charged conductor has charge on its

0%
outside surface
0%
surrounding
0%
middle point
0%
inner surface

In series combination of resistances:

0%
p.d. is same across each resistance.
0%
total resistance is reduced
0%
current is same in each resistance
0%
all above are true.

Explanation

Components connected in series are connected along a single path, so the same current flows through all of the components. The current through each of the components is the same, and the voltage across the circuit is the sum of the voltages across each component. In a series circuit, every device must function for the circuit to be complete. One bulb burning out in a series circuit breaks the circuit. A circuit composed solely of components connected in series is known as a series circuit.
The total resistance of resistors in series is equal to the sum of their individual resistances. Hence, the Equivalent resistance is more than the individual resistances because a sum is taken of all the individual resistances. That is,

${ R }_{ total }={ R }_{ 1 }+{ R }_{ 2 }$ . The current is given as

$I={ I }_{ 1 }={ I }_{ 2 }$ .
Below is the diagrammatic representation of 2 resistors

${ R }_{ 1 }\quad and\quad { R }_{ 2 }$ connected in series.

State whether true or false:

Electric charges leak rapidly from the painted edges of a conductor.

0%
True
0%
False

Which is the equivalent resistance when resistors

$3 \Omega$ and

$6 \Omega$ are in parallel ?

0%
$9\, \Omega$
0%
$3\, \Omega$
0%
$2\, \Omega$
0%
$6\, \Omega$

Explanation

Equivalent resistance is given by:

$\dfrac { 1 }{ { R }_{ eq } } =\dfrac { 1 }{ 3 } +\dfrac { 1 }{ 6 } =\dfrac { 1 }{ 2 } \\ \quad \\ { R }_{ eq }=2\Omega$

Copper metal is a:

0%
good conductor of electricity
0%
bad conductor of electricity
0%
magnetic substance
0%
bad conductor of heat
0%
none of these

Why is the fuse wire fitted in a porcelain casing ?

0%
Porcelian is an insulator of electricity
0%
Porcelian is a conductor of electricity
0%
Porcelian is a semiconductor of electricity
0%
None of these.

State True or False :

The materials, which do not allow electric current to pass through them easily, are poor conductors of electricity.

0%
True
0%
False

Which of the following is a conductor?

0%
glass
0%
tungsten
0%
wood
0%
plastic

Name the materials which are used for making the standard resistor.

0%
Chromium
0%
Copper
0%
Nickel
0%
Tungsten

Equivalent resistances is less than either of the two resistances when they are in

0%
series
0%
Parallel
0%
Parallel and series
0%
none of these.

Explanation

Equivalent resistances is less than either of the two resistances when they are connected in parallel.
Components connected in parallel are connected so the same voltage is applied to each component. In a parallel circuit, the voltage across each of the components is the same, and the total current is the sum of the currents through each component. A circuit composed solely of components connected in parallel is known as a parallel circuit.
To find the total resistance of all components, the reciprocals of the resistances of each component is added and the reciprocal of the sum is taken. Hence, the Total resistance will always be less than the value of the smallest resistance. That is,

$\dfrac { 1 }{ { R }_{ total } } =\dfrac { 1 }{ { R }_{ 1 } } +\dfrac { 1 }{ { R }_{ 2 } } \quad that\quad is,\quad R={ { R }_{ total } }^{ -1 }$ . The voltage is given as

$V={ V }_{ 1 }={ V }_{ 2 }$ .
Above is the diagrammatic representation of 2 resistors

${ R }_{ 1 }\quad and\quad { R }_{ 2 }$ connected in parallel.

1 kilowatt hour

$=$ ___________ .

0%
$10.6 \times 10^6$ Joule
0%
$3.6 \times 10^6$ Joule
0%
$30.6 \times 10^6$ Joule
0%
$3.6 \times 10^5$ Joule

Explanation

$1\ watt = 3600\ joule$

$1\ kW = 1000\ watt$

$1\ h=60\times 60 = 3600\ s$

$1\ kWh= 1\ kW\times 1\ hour=1000\ W\times 3600\ s = 1000 \times 3600 joule = 3.6 \times 10^{6}\ J$

The current which is assumed to be flowing in a circuit from positive terminal to negative, is called:

0%
direct current
0%
pulsating current
0%
conventional current
0%
alternating current

A dynamo develops

$0.5 A$ at

$6 V$ . The energy which is generated in one second is

0%
$0.083 J$
0%
$3 J$
0%
$12 J$
0%
none of these

Explanation

Given:

Voltage(V) =

$6V$

Current(I) =

$0.5A$

Time(t) =

$1sec$

Energy generated =

$VIt$

$\Rightarrow$ Energy

$= 6\times 0.5 \times 1=3 J$

The device used for producing current is called a _____.

0%
Voltmeter
0%
Ammeter
0%
Galvanometer
0%
Generator

The insulator of electricity is :

0%
copper
0%
silk
0%
human body
0%
acidulated water

An electric lamp is marked

$60\ W,\ 220\ V$ . The cost of kilo watt hour of electricity is

$Rs.\ 1.25$ . The cost of using thing lamp on

$220\ V$ for

$8\ hrs$ is:

0%
$Rs.\ 0.25$
0%
$Rs.\ 0.60$
0%
$Rs.\ 1.2$
0%
$Rs.\ 4.00$

Explanation

Given:

Power,

$P=60\ W$

Time,

$t=8\ hrs$

Energy consumed per day,

$E=Pt=60\times 8=480\ Whr=\dfrac{480}{1000}=0.48\ kW hr$
Hence total cost,

$C=0.48\times 1.25=Rs. 0.60$

What is the resistance of a wire if its length is doubled,

0%
becomes twice
0%
becomes thrice
0%
remains same
0%
becomes half

Fill in the blank.
Connecting wires in a electric circuit are made of .......

0%
copper
0%
silicon
0%
tin
0%
lead

The conventional direction of flow of current is

0%
negative terminal to positive terminal of the cell.
0%
positive terminal to negative terminal of the cell.
0%
opposite direction of electrons
0%
in direction of electrons.

The unit of current is :

0%
ampere
0%
volt
0%
ohm
0%
coulomb

The smallest resistance that can be obtained by the combination of

$n$ resistors, each of resistance

$R$ is:

0%
$n^2R$
0%
$nR$
0%
$\dfrac{R}{n^2}$
0%
$\dfrac{R}{n}$

Explanation

For smallest resistance, the resistors are to be connected in parallel. The effective resistance

$=$ R/n.

Which of the follwing does not belong to the group formed by the others?

0%
Iron
0%
Tin
0%
Glass
0%
Steel

CBSE Questions for Class 10 Physics Electricity Quiz 1 - MCQExams.com

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Practice Class 10 Physics Quiz Questions and Answers

CBSE Questions for Class 10 Physics Electricity Quiz 1 - MCQExams.com

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Practice Class 10 Physics Quiz Questions and Answers

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