Class 10 Electricity Previous Years Questions

Previous Years Questions Notes Important Questions

Electricity Previous Years Questions

1. Define 1 kilowatt hour. [1 mark] [CBSE 2019]
2. The values of mA and µA are: [1 mark] [CBSE 2020]
   1. 10^-6 A and 10^-9 A respectively
   2. 10^-3 A and 10^-6 A respectively
   3. 10^-3 A and 10^-9 A respectively
   4. 10^-6 A and 10^-3 A respectively
3. A cylindrical conductor of length ‘l’ and uniform area of cross-section ‘A’ has resistance ‘R’. Another conductor of length 2.5 l and resistance 0.5 R of the same material has area of cross-section: [1 mark] [CBSE 2020]
   1. 5 A
   2. 2.5 A
   3. 0.5 A
   4. 1/5 A
4. Define the term electrical resistivity of a material. [1 mark] [CBSE 2019]
5. 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. [CBSE 2023] [2 Mark]
6. 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. [CBSE 2023] [2 Mark]
7. Consider the scale of a voltmeter shown in the diagram and answer the following questions:
   
   1. What is the least count of the voltmeter?
   2. What is the reading shown by the voltmeter?
   3. If this voltmeter is connected across a resistor of 20 Ω, how much current is flowing through the resistor? [2 marks] [CBSE 2019]
8. Plot a graph between current (I) and potential difference (V) and determine the resistance (R) of the resistor. [2 marks] [CBSE 2018]
9. Show how would you join three resistors each of resistance 9 Ω so that the equivalent resistance of the combination is (i) 13.5 Ω (ii) 6 Ω? [3 marks] [CBSE 2018]
10. 1. Write Joule’s law of heating.
    2. Two lamps, one rated 100 W; 220 V, and the other 60 W; 220 V, are connected in parallel to electric mains supply. Find the current drawn by two bulbs from the line, if the supply voltage is 220 V. [3 marks] [CBSE 2018]
11. 1. List the factors on which the resistance of a conductor in the shape of a wire depends.
    2. Why are metals good conductor of electricity whereas glass is a bad conductor of electricity ?Give reason.
    3. Why are alloys commonly used in electrical heating devices? Give reason. [CBSE 2018] [3 Marks]
12. 1. What is meant by resistance of a conductor ? Define SI unit.
    2. List two factors on which the resistance of a rectangular conductor depends.
    3. How will the resistance of a wire be affected if its
       (i) length is doubled, and
       (ii) radius is also doubled ?
       Give justification for your answer. [CBSE 2023] [5 Marks]
13. In an electric circuit three bulbs of 100 W each are connected in series to a source. In another circuit set of three bulbs of the same wattage are connected in parallel to the same source.
    1. Will the bulb in the two circuit glow with the same brightness ? Justify your answer.
    2. Now, ,et one bulb in both th circuits get fused. Will the rest of the bulbs continue to glow in each circuit ? Give reason for your answer. [CBSE 2023] [5 Marks]
14. 1. Three resistors of resistances R₁, R₂ & R₃ are connected (i) in series , & (ii) in parallel. Write expressions for the equivalent resistance of the combination in each case.
    2. Two identical resistors of 12 Ω each are connected to a battery of 3 V. Calculate the ratio of the power consumed by the resulting combinations with minimum resistance & maximum resistance. [CBSE 2019] [5 Marks]
15. 1. Write the relation between resistance & electrical resistivity of the material of a conductor in the shape of a cylinder of length ‘l’ & area of cross section ‘A’ . Hence derive the S.I. unit of electrical resistivity.
    2. Resistance of a metal wire of length 5 m is 100 Ω. If the area of cross section of the wire is 3 x 10^-7 m², calculate the resistivity of the metal. [CBSE 2019] [5 Marks]
16. 1. Two lamps rated 100 W, 220 V& 10 W , 220 V are connected in parallel to 220 V supply , calculate the total current through the circuit.
    2. Two resistors x & y of resistances 2 Ω & 3 Ω respectively are first joined in parallel & then in series . In each case the voltage supplied is 5 V.
       (i) Draw circuit diagrams to show the combination of resistors in each case.
       (ii) Calculate the voltage across the 3 Ω resistor in the series combination of resistors. [CBSE 2020] [5 Marks]
17. 1. State ohm’s law.
    2. How is an ammeter connected in an electric circuit?
    3. The power of a lamp is 100 W. Find the energy consumed by it in 1 minute.
    4. A wire of resistance 5 Ω is bent in the form of a closed circle. Find the resistance between two points at the ends of any diameter of the circle. [5 marks] [CBSE 2020]
18. The values of current (I) flowing through a given resistor (R), for the corresponding values of potential difference (V) across the resistor are as given below :

V(volts)	0.5	1.0	1.5	2.0	2.5	3.0	4.0	5.0
I(Amperes)	0.1	0.2	0.3	0.4	0.5	0.6	0.8	1.0

Plot a graph between current (I) and potential difference (V) and determine the resistance (R) of the resistor. [2 marks] [CBSE 2018]

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