Assertion and Reason Questions from Current Electricity
CBSE class 12 physics 2021 ( Current electricity )
Hey guys!!!! Surbhi here... Hope these assertion and reason questions give you good practice for your board exams ...
- Directions. In the following questions,statement of assertion is followed by a statement of reason. While answering a question, you are required to choose the correct one out of the given four responses and mark it as :-
- A, if both assertion and reason are true and reason is the correct explanation of the assertion.
- B, if both assertion and reason are true but reason is not correct explanation of the assertion.
- C, if assertion is true, but reason is false.
- D, if both assertion and reason are false.
1) Assertion : Current have direction as well as magnitude but still it is not considered vector.
Reason : It does not follow vector addition.
1) A 2) B 3) C 4)D
2) Assertion : The drift velocity of electrons in a conductor is very small, when its two ends are connected to a battery.
Reason : It is because , as the electrons accelerates, they get scattered or deflected on suffering collisions against the positive ions in the conductor.
1) A 2) B 3) C 4)D
3) Assertion: The electric bulb glows immediately, when switched on.
Reason : The drift velocity of electrons in a metallic wire is very high.
4) Assertion : Insulators do not allow flow of current through themselves.
Reason : They have no free electrons.
1) A 2) B 3) C 4)D
5) Assertion : The resistivity of a semiconductor increases with temperature.
Reason : The atoms of semiconductor vibrate with larger amplitude at higher temperatures thereby increasing its resistivity.
1) A 2) B 3) C 4)D
6) Assertion : Copper wires are used as the connecting wires in an electrical circuit.
Reason : Copper can be drawn into thin wires.
1) A 2) B 3) C 4)D
7) Assertion : Manganin or constantan is used for making standard resistances.
Reason : Their resistivity is high, while temperature coefficient is low.
1) A 2) B 3) C 4)D
8) Assertion: A circular wire has resistance R. Then its resistance between two diametrically opposite points will be R/4.
Reason : The two semicircular portions, each having resistance R/2, form a parallel combination.
1) A 2) B 3) C 4)D
9) Assertion : The resistors are connected in parallel, when resistance in the circuit is to be decreased.
Reason : On connecting the resistors in parallel, the potential difference across a resistor is proportional to its resistance.
1) A 2) B 3) C 4)D
10) Assertion : An electric bulb becomes dim, when the electric heater in parallel circuit is switched on.
Reason : Dimness decreases after sometimes.
1) A 2) B 3) C 4)D
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