Class Notes NCERT Solutions for CBSE Students
Question: Sate Ohm’s law.
Answer: Physical conditions remaining same, the electric current flowing through a conductor is directly proportional to the potential different across the two ends of the conductor.
Question: What is meant by resistance?
Answer: It is the opposition offered to the flow of electrons by a conductor.
Question: What are the units of resistance?
Answer: It is measured in ohm.
Question: What is meant by 1 ohm resistance?
Answer: The resistance of a conductor is said to be 1 ohm if under a potential difference of 1 volt a current of one ampere flows through the conductor.
Question: What will happen to the current flowing through a conductor, if the potential difference is doubled?
Answer: The current is also doubled.
Question: What are the factors on which resistance of conductor depends?
Answer: The resistance of a conductor depends upon:
(i) the length of the conductor and
(ii) the area of cross-section of the conductor
Question: What is meant by equivalent resistance?
Answer: It is the combination of a number of resistances.
Question: When do we say that the resistors are connected in series?
Answer: When the current through each resistor is same.
Question: When do we say that the resistors are connected in parallel?
Answer: When the potential difference across each resistor is same.
Question: What are the factors on which resistivity of a material depends?
Answer: It depends only upon the nature of the conductor.
Question: What will happen to the current in a circuit, it its resistance is doubled?
Answer: The current becomes half.
Question: What will happen to the resistance of the circuit, if the current through it is doubled?
Answer: No change, since resistance does not depend upon current.
Question: What is the cause of resistance?
Answer: During heir motion through a conductor, the electrons suffer collisions due to other electrons or the ions of the conductor. As a result, there motion is opposed. This opposition is the case of resistance.
