Class 10 Science · Chapter 11

Electricity

363 Class 10 Science questions on Electricity from the NCERT textbook, NCERT Exemplar and CBSE board papers 2018–2026, each with its answer and a step-by-step solution.

NCERT exercises

Exercises (18) Intext Questions (Page 172) (3) Intext Questions (Page 174) (3) Intext Questions (Page 181) (5) Intext Questions (Page 185) (2) Intext Questions (Page 188) (5) Intext Questions (Page 190) (3) Intext Questions (Page 192) (2)

NCERT Exemplar exercises

Multiple Choice Questions (18) Short Answer Questions (10) Long Answer Questions (7)

CBSE Class 10 Science previous year papers, with answers →

Questions · page 12 of 19

Q221 CBSE 2023
Potential difference can also be represented as :
1. (a) $\frac{Work done}{Charge}$
2. (b)Work done $\times$ Charge
3. (c)Work done $\times$ Charge $\times$ Time
4. (d) $\frac{Work done \times Charge}{Time}$
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(a) $\frac{Work done}{Charge}$

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Q222 CBSE 2023
For verifying Ohm's law, we design an electric circuit diagram in which we show the arrangement of different circuit components. We find that with respect to the resistor, the :
1. (a)ammeter is connected in parallel and the voltmeter in series.
2. (b)ammeter is connected in series and the voltmeter in parallel.
3. (c)ammeter and voltmeter are both connected in series.
4. (d)ammeter and voltmeter are both connected in parallel.
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(b) ammeter is connected in series and the voltmeter in parallel.

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Q223 CBSE 2023
You have a thin resistance wire having a thick plastic insulation. A decrease in the resistance of this wire would be produced if somehow we increase the :
1. (a)thickness of the plastic insulation
2. (b)temperature of the wire
3. (c)length of the wire
4. (d)diameter of the wire
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(d) diameter of the wire

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Q224 CBSE 2023
Two LED bulbs of 12 W and 6 W are connected in series. If the current flowing through 6 W bulbs is $0.005$ A, the current that flows through 12 W bulb is :
1. (a) $0.005$ A
2. (b) $0.01$ A
3. (c) $0.0025$ A
4. (d) $0.02$ A
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(a) $0.005$ A

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Q225 CBSE 2023
A material used for making heating elements of electrical heating devices should have :
1. (a)High resistivity and high melting point.
2. (b)High resistivity and low melting point.
3. (c)Low resistivity and high melting point.
4. (d)Low resistivity and low melting point.
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(a) High resistivity and high melting point.

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Q226 CBSE 2023
An electric iron of 1500 W, 200 V and a flash light of 500 W, 200 V are used in homes. The rating of fuse to be used should be
1. (a) $5$ A
2. (b) $10$ A
3. (c) $15$ A
4. (d) $20$ A
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(b) $10$ A

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Q227 CBSE 2023
How much work is done in moving a charge of $3$ C across two points having a potential difference of $12$ V ?
1. (a) $4$ J
2. (b) $36$ J
3. (c) $54$ J
4. (d) $216$ J
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(b) $36$ J

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Q228 CBSE 2023
In the following diagram, the position of the needle is shown on the scale of a voltmeter. The least count of the voltmeter and the reading shown by it respectively are :
1. (a) $0.15$ V and $1.6$ V
2. (b) $0.05$ V and $1.6$ V
3. (c) $0.15$ V and $1.8$ V
4. (d) $0.05$ V and $1.8$ V
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(c) $0.15$ V and $1.8$ V

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Q229 CBSE 2023
In a resistive circuit if the current is increased to two times, the percentage change in the amount of heat dissipated in the circuit would be :
1. (a) $400%$
2. (b) $300%$
3. (c) $200%$
4. (d) $100%$
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(b) $300%$

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Q230 CBSE 2023
The resistance of a resistor is reduced to half of its initial value. If other parameters of the electrical circuit remain unaltered, the amount of heat produced in the resistor will become :
1. (a)four times
2. (b)two times
3. (c)half
4. (d)one fourth
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(b) two times

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Q231 CBSE 2023
An electric kettle consumes 1 kW of electric power when operated at 220 V. The minimum rating of the fuse wire to be used for it is
1. (a)1 A
2. (b)2 A
3. (c)4 A
4. (d)5 A
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(d) 5 A

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Q232 CBSE 2023
The resistance of a wire does not depend on its :
1. (a)Length
2. (b)Area of cross-section
3. (c)Shape
4. (d)Material
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(c) Shape

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Q233 CBSE 2023
From a power station, the power is transmitted to distant places in the form of AC at a very high voltage because :
1. (a)electricity is less dangerous at high voltages.
2. (b)electricity is generated at high voltage.
3. (c)transmission is faster at high voltage.
4. (d)at high voltage, the loss of energy during transmission is less.
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(d) at high voltage, the loss of energy during transmission is less.

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Q234 CBSE 2023
If the current $I$ through a resistor is increased by $100%$ (at constant temperature), the increase in power dissipated will be
1. (a) $100%$
2. (b) $200%$
3. (c) $300%$
4. (d) $400%$
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(c) $300%$

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Q235 CBSE 2023
Two LED bulbs of 10W and 5W are connected in series. If the current flowing through 5W bulb is 0.005A, the current flowing through 10W bulb is :
1. (a) $0.02$ A
2. (b) $0.01$ A
3. (c) $0.005$ A
4. (d) $0.0025$ A
Show answer

(c) $0.005$ A

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Q236 CBSE 2023

Let the resistance of an electrical device remain constant, while the potential difference across its two ends decreases to one fourth of its initial value. What change will occur in the current through it? State the law which helps us in solving the above stated question.

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The current falls to one fourth of its initial value; the law used is Ohm's law.
The current also falls to one fourth of its initial value, $I_{2} = \frac{I _{1}}{4}$ . The law used is Ohm’s law: at constant temperature the current through a conductor is directly proportional to the potential difference across its ends, $V = I R$ .

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Q237 CBSE 2023

Three resistors of $6 Ω$ , $4 Ω$ and $4 Ω$ are connected together so that the total resistance is $8 Ω$ . Draw a diagram to show this arrangement and give reason to justify your answer.

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Two $4 Ω$ resistors in parallel ( $2 Ω$ ) joined in series with the $6 Ω$ resistor give $8 Ω$ .
Connect the two $4 Ω$ resistors in parallel and join this pair in series with the $6 Ω$ resistor, as in the diagram. Reason: for the parallel pair $\frac{1}{R _{p}} = \frac{1}{4} + \frac{1}{4} = \frac{1}{2}$ , so $R_{p} = 2 Ω$ ; in series with $6 Ω$ the total is $R = 6 + 2 = 8 Ω$ .

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Q238 CBSE 2023

$V$ – $I$ graph for two conducting wires A and B are as shown. If both wires are of the same length and same diameter, which of the two is made of a material of high resistivity ? Give reasons to justify your answer.

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Wire B has higher resistivity: its steeper $V$ – $I$ line means greater resistance, and the wires have the same length and diameter.
Wire B is made of the material of higher resistivity. On this graph $V$ is plotted on the vertical axis and $I$ on the horizontal axis, so the slope of each line is $V / I$ , which by Ohm's law is the resistance of that wire. The line for B is steeper, so $R_{B} > R_{A}$ . Since $R = ρ L / A$ and both wires have the same length $L$ and the same diameter, and hence the same area of cross-section $A$ , the ratio $R_{B} / R_{A} = ρ_{B} / ρ_{A}$ . Therefore $ρ_{B} > ρ_{A}$ , that is, B has the higher resistivity.

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Q239 CBSE 2023

State Ohm’s law. List two factors on which the resistance of a cylindrical conductor at a given temperature depends. A wire was drawn into a wire of double its length by melting it. If the resistance of the old wire was $R$ , what is the resistance of the new wire ?

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Ohm's law is $V \propto I$ at constant temperature; resistance depends on length and area; the redrawn wire has resistance $4 R$ .
Ohm's law: the potential difference across the ends of a metallic conductor is directly proportional to the current flowing through it, provided its temperature remains the same; that is, $V \propto I$ , so $V = I R$ , where the constant $R$ is the resistance of the conductor. Two factors: (i) the length of the conductor - $R \propto l$ ; (ii) the area of cross-section of the conductor - $R \propto 1/ A$ . (It also depends on the material, through its resistivity $ρ$ .) Resistance of the new wire: melting and redrawing leaves the volume unchanged, so with $l^{'} = 2 l$ the area becomes $A^{'} = A /2$ , and $R^{'} = \frac{ρ ( 2 l )}{A /2} = 4 \frac{ρl}{A} = 4 R$ . The new wire has a resistance of $4 R$ .

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Q240 CBSE 2023
(i) Write the formula for finding the value of the equivalent resistance of three resistors of resistance $R_{1}$ , $R_{2}$ and $R_{3}$ , when the resistors are connected in
1. (i)series, and
2. (ii)parallel. (ii) List two advantages of connecting electrical devices in parallel with the source of electricity instead of connecting them in series.
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Resistances add in series and their reciprocals add in parallel; parallel devices each get full voltage and work independently.
(i) In series: $R_{s} = R_{1} + R_{2} + R_{3}$ . In parallel: $\frac{1}{R _{p}} = \frac{1}{R _{1}} + \frac{1}{R _{2}} + \frac{1}{R _{3}}$ . (ii) Two advantages of a parallel connection: (1) Each device receives the full potential difference of the source, so every device works at its rated voltage; in series the voltage is divided and no device gets the full voltage. (2) Each device is on its own separate path, so it can be switched on and off independently and a fault or a break in one device does not stop the others; in series one break stops everything. (A further advantage is that the total resistance of the circuit is reduced, so a larger total current can be drawn and each device can take the different current it needs.)

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