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CBSE Class 10 Physics Electricity Important Questions and Answers: Using the help of these important questions from the chapter Electricity, students appearing in CBSE Class 10 Science board examination can achieve their dream scores. These questions have been specially chosen by subject experts keeping in mind the revised syllabus, latest sample paper and board guidelines.
Electricity is actually the 11th Chapter according to the latest syllabus and updated NCERT Textbook. However, earlier it appeared as Chapter 12. Chapter 11 Electricity is a part of Unit IV. The other chapter in this unit is Magnetic effects of current which is Chapter 12.
The topics covered in this chapter are: Electric current, potential difference and electric current. Ohm’s law; Resistance, Resistivity, Factors on which the resistance of a conductor depends. Series combination of resistors, parallel combination of resistors and its applications in daily life. Heating effect of electric current and its applications in daily life. Electric power, Interrelation between P, V, I and R.
Also Check: CBSE Class 10 Science Syllabus 2022-23
CBSE Class 10 Physics Electricity Important Questions
MULTIPLE-CHOICE QUESTIONS
Q.1.When electric current is passed, electrons move from:
(a) high potential to low potential.
(b) low potential to high potential.
(c) in the direction of the current.
(d) against the direction of the current.
Q.2. The unit of resistivity is:
(a) V A
(b) V A
(c) V m /A
(d) VA/m
Q.3. What is the commercial unit of electrical energy?
(a) Joules
(b) Kilojoules
(c) Kilowatt-hour
(d) Watt-hour
Q.4. The instrument used for measuring electric current is :
(a) Ammeter
(b) Galvanometer
(c) Voltmeter
(d) Potentiometer
Q.5. Electrical resistivity of any given metallic wire depends upon
(a) its thickness
(b) its shape
(c) nature of the material
(d) its length
Q.6. In an electrical circuit two resistors of 2 Ω and 4 Ω respectively are connected in series to a 6 V battery. The heat dissipated by the 4 Ω resistor in 5 s will be
(a) 5 J
(b) 10 J
(c) 20 J
(d) 30 J
Q.7. The heating element of an electric iron is made up of:
(a) copper
(b) nichrome
(c) aluminium
(d) iron
Q.8. Work of 14 J is done to move 2 C charge between two points on a conducting wire. What is the potential difference between the two points?
(a) 28 V
(b) 14 V
(c) 7 V
(d) 3.5 V
Q.9. While a cell is being charged, energy is converted into energy.
- mechanical, electrical
- electrical, chemical
- heat, electrical
- chemical, heat
Q.10. The unit of potential difference is :
(a) Volt
(b) Ohm
(c) Ampere
(d) Faraday
Q.11. Copper is not preferred to make fuse wire because it .
- is a good conductor of electricity
- has a low melting point
- has a high melting point
- is not easily available
Q.12. Coulomb is the SI unit of:
(a) Charge
(b) current
(c) potential difference
(d) resistance
ASSERTION-REASON TYPE QUESTIONS
Following questions consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Q.1.. Assertion (A): When resistances are connected between the same two points they are said to be in series.
Reason(R): When resistors are connected in series the current through each resistor is the same.
Q.2. Assertion (A) : Tungsten metal is used for making filaments of incandescent lamps.
Reason (R) : The melting point of tungsten is very low.
Q.3. Assertion (A): If a graph is plotted between potential difference and current the graph is a straight line passing through the origin.
Reason(R): current is directly proportional to the potential difference.
Q.4. Assertion (A) : Longer wires have greater resistance and the smaller wires have lesser resistance.
Reason (R) : Resistance is inversely proportional to the length of the wire.-
Q.5. Assertion (A) : Alloys are commonly used in electrical heating devices, like electrical iron, toasters etc.
Reason (R) : Alloys do not oxidise (burn) readily at high temperatures.
6. Assertion (A) : Bending a wire does not affect electrical resistance.
Reason (R) : Resistance of a wire is proportional to resistivity of material.
Q.7. Assertion (A): A cell converts chemical energy into electrical energy.
Reason(R): A cell maintains a potential difference across its terminals due to chemical reactions.
CASE STUDY BASED QUESTION
Electrical resistivities of some substances at 20°C are given in the table. Based on the info in the table, answer the given questions.
|
Silver |
1.60 X 10-8 m |
|
Copper |
1.62 X 10-8 m |
|
Tungsten |
5.2 X 10-8 m |
|
Mercury |
94 X 10-8 m |
|
Iron |
10 X 10-8 m |
|
Nichrome |
100 X 10-8 m |
- Which is a better conductor of electric current ?
(A) Silver (B) Copper (C) Tungsten (D) Mercury
- Which element will be used for electrical transmission lines ?
(A) Iron (B) Copper (C) Tungsten (D) mercury U
- Nichrome is used in the heating elements of electric heating device because:
(A) It has high resistivity
(B) It does not oxidise readily at high temperature
(C) Both of the above
(D) None of the above U
- Series arrangement is not used for domestic circuits because:
(A) Current drawn is less
(B) Current drawn is more
(C) Neither of the above
(D) Both of the above
TWO MARKS QUESTIONS
Q.1.Calculate the number of electrons that would flow per second through the cross- section of a wire when 1 A current flows in it.
Q.2. Define the following terms:
(a) one ampere (b) 1 volt.
Q.3. Keeping the potential difference constant, the resistance of a circuit is doubled. By how much does the current change?
Q.4. How much work is done in moving a charge of magnitude 3 C across two points having a potential difference of 12 V?
Q.5. Define electric power. Write an expression relating electric power, potential difference and resistance.
Q.6.Give reason for the following:
- Tungsten used almost exclusively for filament of electric lamp.
- Why do we use copper and aluminium wires for transmission of electric current?
Q.7. Distinguish between resistances in series and resistances in parallel.
8. What is the better way of connecting lights and other electrical appliances in domestic wiring? Why?
THREE MARKS QUESTIONS
Q.1. (a) List the factors on which the resistance of a conductor in the shape of a wire depends.
(b) Why are metals good conductors of electricity whereas glass is a bad conductor of electricity? Give reasons..
(c) Why are alloys commonly used in electrical heating devices? Give reason.
2. A nichrome wire has a resistance of 10 Ω. Find the resistance of another nichrome wire, whose length is three times and area of cross-section four times the first wire.
Q.3. State the formula co-relating the electric current flowing in a conductor and the voltage applied across it. Also, show this relationship by drawing a graph. What would be the resistance of a conductor, if the current flowing through it is 0.35 ampere when the potential difference across it is 1.4 volt?
4.Calculate the total cost of running the following electrical devices in April month if the rate of 1 unit of electricity is Rs. 6.00. (i) Electric heater of 1000 W for 5 hours daily. (ii) Electric refrigerator of 400 W for 10 hours daily
5. (i) Consider a conductor of resistance ‘R’, length ‘L’, thickness ‘d’ and resistivity ‘ρ’. Now this conductor is cut into four equal parts. What will be the new resistivity of each of these parts? Why?
(ii) Find the resistance if all of these parts are connected in:
(a) Parallel (b) Series
(iii) Out of the combinations of resistors mentioned above in the previous part, for a given voltage which combination will consume more power and why?
Also Check: CBSE Class 10 Science Sample Paper 2022-23
To get the answers to these questions, click on the link below:
Electricity has revolutionised the world and our lives. It has an important place in modern society. As an controllable and convenient form of energy, it is utilised for a variety of chores in homes, at schools, hospitals, industries and so on. Thus, students should not just cram the syllabus to score marks in exam but try to actually grasp the content of the chapters as it is a very important topic for academic and personal life as well.
All the best!
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