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## Class 10 Physics (India)

# Electricity class 10: CBSE previous question paper problems

Prepare for class 10 CBSE exam using this analysis of the last 10 years’ question papers from the chapter Electricity. Explore common and important questions, with solutions.

Let's explore some of the main types of problems that appeared in the last ten years of CBSE board exams, arranged by subtopic.

Happy practicing!

## Electric current and circuit

**Type A. Definitions**

*Frequency of appearance:*start color #ff9c39, \bigstar, end color #ff9c39, start color #ff9c39, \bigstar, end color #ff9c39, start color gray, \bigstar, \bigstar, \bigstar, end color gray

**Q1. What is an electric circuit? Distinguish between an open and a closed circuit.**

[2 marks, AI 2009]

**Type B. Applying the definitions of Coulomb and current**

*Frequency of appearance:*start color #ff9c39, \bigstar, end color #ff9c39, start color gray, \bigstar, \bigstar, \bigstar, \bigstar, end color gray

**Q2. A current of 10, space, start text, A, end text flows through a conductor for two minutes.**

**(start text, i, end text) Calculate the amount of charge passed through any area of cross section of the conductor.**

**(start text, i, i, end text) If the charge of an electron is 1, point, 6, times, 10, start superscript, minus, 19, end superscript, space, start text, C, end text, then calculate the total number of electrons flowing.**

[3 marks, Board Term I, 2013]

Feeling stuck?

- Understand the concept better with this
**video**: Unit of charge (Coulombs)

## Electric potential and potential difference

**Type C. Relation between potential difference and work**

*Frequency of appearance:*start color #ff9c39, \bigstar, end color #ff9c39, start color gray, \bigstar, \bigstar, \bigstar, \bigstar, end color gray

**Q3. (start text, a, end text) Define the term 'volt'.**

**(start text, b, end text) State the relation between work, charge and potential difference for an electric circuit.**

**Calculate the potential difference between the two terminals of a battery if 100, space, start text, J, end text of work is required to transfer 20, space, start text, C, end text of charge from one terminal of the battery to the other.**

[3 marks, AI 2009]

Feeling stuck?

- Get more practice with this
**exercise**: Voltage and work - Understand the concept better with these
**videos**: (start text, i, end text) Intro to potential difference (& voltage), (start text, i, i, end text) Solved example: Potential difference & work done

## Circuit diagram

**Type D. Drawing circuit elements and circuits**

*Frequency of appearance:*start color #ff9c39, \bigstar, end color #ff9c39, start color gray, \bigstar, \bigstar, \bigstar, \bigstar, end color gray

**Q4. Draw a schematic diagram of an electric circuit consisting of a battery of two cells each of 1, point, 5, space, start text, V, end text, 5, space, \Omega, 10, space, \Omega and 15, space, \Omega resistors and a plug key, all connected in series.**

[1 mark, AI 2009]

**Q5. Draw the symbols of commonly used components in electric circuit diagrams for**

**(start text, i, end text) an electric cell**

**(start text, i, i, end text) open plug key**

**(start text, i, i, i, end text) wires crossing without connection**

**(start text, i, v, end text) variable resistor**

**(start text, v, end text) battery**

**(start text, v, i, end text) electric bulb**

**(start text, v, i, i, end text) resistance.**

[4 marks, Board Term I 2017]

## Ohm's law

**Type E. V-I graph and applying Ohm's law**

*Frequency of appearance:*start color #ff9c39, \bigstar, end color #ff9c39, start color #ff9c39, \bigstar, end color #ff9c39, start color #ff9c39, \bigstar, end color #ff9c39, start color gray, \bigstar, \bigstar, end color gray

**Q6. State Ohm's law. Draw a labelled circuit diagram to verify this law in the laboratory. If you draw a graph between the potential difference and current flowing through a metallic conductor, what kind of curve will you get? Explain how you would use this graph to determine the resistance of the conductor.**

[5 marks, Board Term I, 2016]

Feeling stuck?

- Understand the concept better with these
**videos**: (start text, i, end text) Introduction to circuits and Ohm's law, (start text, i, i, end text) Solved example: Ohms law, (start text, i, i, i, end text) Ohm's law graph (verifying Ohm's law), (start text, i, v, end text) Solved example: (Ohm's law graph).

## Factor on which the resistance of a conductor depends

**Type F. Word problems and numericals**

*Frequency of appearance:*start color #ff9c39, \bigstar, \bigstar, \bigstar, end color #ff9c39, start color #ff9c39, \bigstar, end color #ff9c39, start color #ff9c39, \bigstar, end color #ff9c39

**Q7. (start text, a, end text) List the factors on which the resistance of a conductor in the shape of a wire depends.**

**(start text, b, end text) Why are metals good conductors of electricity while glass is a bad conductor of electricity? Give reasons.**

**(start text, c, end text) Why are alloys commonly used in electrical heating devices? Give reason.**

[3 marks, 2018 (AI, Delhi, Foreign)]

**Q8. The resistance of a wire of 0, point, 01, space, start text, c, m, end text radius is 10, space, \Omega. If the resistivity of the material of the wire is 50, times, 10, start superscript, minus, 8, end superscript, space, \Omega, start text, m, end text, find the length of the wire.**

[3 marks, Board Term I, 2014]

**Q9. Define resistance of a conductor. State the factors on which resistance of a conductor depends. Name the device which is often used to change the resistance without changing the voltage source in an electric circuit.**

**Calculate the resistance of 50, space, start text, c, m, end text length of wire of cross sectional area 0, point, 01, space, start text, m, m, end text, squared and of resistivity 5, times, 10, start superscript, minus, 8, end superscript, space, \Omega, start text, m, end text.**

[5 marks, Board Term I, 2009]

Feeling stuck?

- Understand the concept better with this
**video**: Resistivity and conductivity

## Resistance of system of resistors

**Type G. Calculating equivalent resistance and currents**

*Frequency of appearance:*start color #ff9c39, \bigstar, \bigstar, \bigstar, end color #ff9c39, start color #ff9c39, \bigstar, end color #ff9c39, start color #ff9c39, \bigstar, end color #ff9c39

**Q10. Two resistors, of resistances 5, space, \Omega and 10, space, \Omega respectively are to be connected to a battery of e.m.f. 6, space, start text, V, end text so as to obtain**

**(start text, i, end text) minimum current flowing**

**(start text, i, i, end text) maximum current flowing.**

**(start text, a, end text)How will you connect the resistances in each case?**

**(start text, b, end text) Calculate the strength of the total current in the circuit in the two cases.**

[3 marks, Delhi 2009]

**Q11. Consider the following electric circuit.**

**(start text, i, end text) Which two resistors are connected in series?**

**(start text, i, i, end text) Which two resistors are connected in parallel?**

**(start text, i, i, i, end text) If every resistor is 2, space, \Omega, what current will flow in the circuit?**

[3 marks, Delhi 2009]

**Type H. Derivations**

*Frequency of appearance:*start color #ff9c39, \bigstar, \bigstar, end color #ff9c39, start color gray, \bigstar, \bigstar, \bigstar, end color gray

**Q12. Deduce the expression for the equivalent resistance of the parallel combination of three resistors start text, R, end text, start subscript, 1, end subscript, start text, R, end text, start subscript, 2, end subscript, and start text, R, end text, start subscript, 3, end subscript.**

[2 marks, Foreign 2010]

Feeling stuck?

- Get more practice with these
**exercises**: (start text, i, end text) Finding equivalent resistance, (start text, i, i, end text) Identifying types of resistor combinations, (start text, i, i, i, end text) Simplifying resistor networks, (start text, i, v, end text) Finding currents and voltages (pure circuits). - Understand the concept better with these
**videos**: (start text, i, end text) Series resistors, (start text, i, i, end text) Parallel resistors (part 1), (start text, i, i, i, end text) Parallel resistors (part 2), (start text, i, v, end text) Parallel resistors (part 3), (start text, v, end text) Example: Analyzing a more complex resistor circuit, (start text, v, i, end text) Solved example: Finding current & voltage in a circuit.

## Heating effect of electric current

**Type I. Relation between heat produced in a wire and resistance**

*Frequency of appearance:*start color #ff9c39, \bigstar, end color #ff9c39, start color gray, \bigstar, \bigstar, \bigstar, \bigstar, end color gray

**Q13. A fuse wire melts at 5, space, start text, A, end text. If it is desired that the fuse wire of the same material melt at 10, space, start text, A, end text, then should the new fuse wire be of smaller or larger radius than the earlier one? Give reasons for your answer.**

[3 marks, Board Term I, 2014]

**J. Derivations and conceptual problems**

*Frequency of appearance:*start color #ff9c39, \bigstar, end color #ff9c39, start color gray, \bigstar, \bigstar, \bigstar, \bigstar, end color gray

**Q14. Derive an expression for the heat produced in a conductor of resistance R when a current I flows through it for some time t.**

**Two identical resistors of resistance R are connected in series with a battery of potential difference V for time t. The resistors are then connected in parallel with the same battery for the same time t. Compare the heat produced in the two cases.**

[5 marks, Foreign 2010]

Feeling stuck?

- Get more practice with this
**exercise**: Calculating heat dissipated in circuits. - Understand the concept better with these
**videos**: (start text, i, end text) Heating effect of current, (start text, i, i, end text) Solved example - Calculating power & heat dissipated.

## Electric power

**Type K. Calculating power and energy consumed**

*Frequency of appearance:*start color #ff9c39, \bigstar, \bigstar, \bigstar, \bigstar, end color #ff9c39, start color gray, \bigstar, end color gray

**Q15. Two lamps, one rated 100, space, start text, W, end text, ;, space, 220, space, start text, V, end text, and the other 60, space, start text, W, end text, ;, space, 220, space, start text, V, end text, are connected in parallel to electric mains supply. Find the current drawn by the two lamps from the line, if the supply voltage is 220, space, start text, V, end text.**

[2 marks, Board Term I, 2014]

**Q16. (start text, a, end text) How should two resistors, with resistances R, start subscript, 1, end subscript, space, \Omega and R, start subscript, 2, end subscript, space, \Omega be connected to a battery of e.m.f. V volts so that the electrical power consumed is minimum?**

**(start text, b, end text) In a house, 3 bulbs of 100 watt each are lighted for 5 hours daily, 2 fans of 50 watt each are used for 10 hours daily and an electric heater of 1, point, 00, space, start text, k, W, h, end text is used for half an hour daily. Calculate the total energy consumed in a month of 31 days and its cost at the rate of start text, ₹, space, 3, point, 60, slash, k, W, h, end text.**

[5 marks, Board Term I, 2017]

Feeling stuck?

- Get more practice with this
**exercise**: Bulbs connected in series or parallel. - Understand the concept better with these
**videos**: (start text, i, end text) Electric power & energy, (start text, i, i, end text) Solved example: Power dissipated in bulbs, (start text, i, i, i, end text) Solved example - Cost of operation of electrical device.

## Want to join the conversation?

- What does it mean by resistor R1 is shorted and does not contribute to equivalent resistance in Q11] iii) solution?(2 votes)
*Hey Nandini*

Take an example involving yourself - If you have an option of going to the same destination through a flat route as well as a steep hilly route, which one would you choose? Generally, the flat route - because it is easier

Current always flows through the easiest path it gets.

As you know, a resistor is something that opposes the flow of current. Hence, if the current finds a path with no resistor at a place, it would go through that instead of the path with the resistor. This is also called**short-circuiting**.

In Q)11 iii), you see that there is a wire with no resistor joining the same points which R1 does; the current rather flows through the non-resistor path. Here we say, R1 is shorted. Hence R1 has no impact on the current flowing through the circuit as no current is flowing through R1.*Hope it helps. Feel free to comment if your doubt persists...Have fun learning :)*(8 votes)

- diffrentiate between joules and watt(2 votes)
- Joule is the SI Unit of Energy while Watt is the SI Unit of Power.(5 votes)

- Is this both electricity and its effects and magnetic effects of electric current, or one only?(1 vote)
- Electric current can have 3 effects: (i)Heating Effect; (ii)Magnetic Effect & (iii)Chemical Effect

Thus, the magnetic effect of electric current is just one of electric current's effect

Hope it helps :)(3 votes)

- can you guys explain to me functions and the functioning of a fuse wire?

I love what you do at Khan Academy. Thank you for the unrelentless hard work you guys put it. Mad respect!(2 votes)- Hey @
**Swirly Candy**a fuse is a simple wire. That's how it looks. But this wire has a really low melting point that when some extra amount of electricity passes it, it melts. When it melts it breaks the circuit. If it breaks the circuit well you can imagine what can happen.*So this fuse wire is to help cut extra electricity from passing through to prevent overheating or overloading the appliance connected.**Hope this helps*

Nolan R.T :)(3 votes)

- diffrentiate between series and parralles(2 votes)
- In series combination(1. The potential difference is divided[v=v1+v2]. 2. It is not used in domestic circuits because if one of the middle appliances goes off, the other appliances will also get affected. 3. Current is the same throughout the series combo. 4. The resistors are connected in series one after the other.)

In the parallel combination(1. The Potential Difference in the parallel combo is divided. 2. It is used in domestic circuits because if one of the appliances goes off, then also the other appliances aren't affected. 3. The current is divided in the parallel combo. 4. The resistors here are connected parallel to each other by joining end to end.)(2 votes)