Physics important questions in electricity lesson class 10
Answers
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Q1. What does an electric circuit mean?
Ans. A continuous conducting path consisting of wires and other resistances and a switch between the two terminals of a cell or a battery along which an electric current flow is called a circuit.
Q2. Define the unit of current.
Ans. The unit of current is Ampere. 1 Ampere is said to be when 1 coulomb of charge flow through any cross section of a conductor in 1 second.
Q3. Calculate the number of electrons constituting one coulomb of charge.
Ans. 1C = 6 × 1018 electrons.
Q4. Name a device that helps to maintain a potential difference across a conductor.
Ans. A battery of many cells or a single cell can maintain potential difference.
Q5. What is meant by saying that the potential difference between two points is 1 V?
Ans. The potential difference between two points is said to be 1 V if 1 Joule of work is done in moving 1 Coulomb of charge from one point to another point
Q7. How much energy is given to each coulomb of charge passing through a 6 V battery?
Ans. Amount of charge = 1 coulomb or 1C
Potential difference = 6 V
Energy or work done = ?
Work done or energy = V × Q[Q is the amount of charge flowing between two points at potential difference V = 6
i.e., W = V × Q
W = 6 × 1
Work done or energy = 6 joules
Q8. On what factors do the resistance of a conductor depend?
Ans. Resistance of a conductor depends on:
(a) Length of a conductor. Resistance of a conductor is directly proportional to the length of a conductor. If length increases resistance will also increase.
(b) Area of cross section of a conductor. The resistance of a conductor is inversely proportional to the area of the cross section of a conductor.
(c) Effect of material of a conductor. The resistance of a conductor also depends on the material of a conductor.
E.g. The resistance of nichrome wire is 60 times more than that of copper wire as nichrome has high electrical resistance
(d) Effect of temperature. The resistance of all pure metals increases on increasing the temperature and decreases on decreasing the temperature.
Q9. Will current flow more easily through a thick wire or a thin wire of the same material, when connected to the same source? Why?
Ans. The current will flow more easily through a thick wire as compared to the thin wire because the resistance of thick wire is less than that of thin wire. Less resistance, means more current.
Q10. Let the resistance of an electrical component remains constant while the potential difference across the two ends of the component decreases to half of Us fanner value. What change will occur in the current through it?
Ans. Amount of current will be halved.