Assertion-Reason Type Questions (Q. Nos. 13-14)
In each of the following questions, a statement of Assertion is given by me con
tatement of Assertion is given by the corresponding
statement of Reason. Of the statements, mark the correct answer as
(a) If both Assertion and Reason are true and Reason is the correct explanation of
Assertion.
(b) If both Assertion and Reason are true, but Reason is not the correct explanation of
Assertion.
(c) If Assertion is true, but Reason is false.
(d) I Assertion is false, but Reason is true..
13. Assertion The magnetic field produced by a current carrying solenoid is
independent of its length and cross-sectional area.
Reason The magnetic field inside the solenoid is uniform.
14. Assertion Graphite is slippery to touch.
Reason Various layers of carbon atoms in graphite are held together by weak
van der Waals' forces.
Answers
Case 1: Both the Assertion and Reason are true, but Reason is not the correct explanation of
Assertion (Option B)
Case 2: Both Assertion and Reason are true and Reason is the correct explanation of Assertion (option A)
Case 1:
Assertion: The magnetic field produced by a current carrying solenoid is independent of its length and cross-sectional area.
Reason: The magnetic field inside the solenoid is uniform.
The magnetic field, B, within the solenoid at point, P was determined as:
B = [(μ0nI)/2][cosθ1 – cosθ2]
Where n denotes the number of turns for one unit length, i.e., n/l
This indicated that the magnetic field, B, did not depend on the cross-sectional area and length of the solenoid.
Additionally, this magnetic field was uniform and was seen to be parallel to the solenoid’s axis.
However, this reason did not explain the assertion.
Thus, though the assertion and reasons were factually correct, the reason did not provide an explanation for the assertion.
Case 2:
Assertion: Graphite is slippery to touch.
Reason: Various layers of carbon atoms in graphite are held together by weak van der Waals' forces.
Graphite is an allotrope of carbon. The different layers in the substance consist of carbon atoms that are bound with one another by weak van der Waals' forces. These layers often slip over one another, making Graphite very slippery.
In this case, the assertion and reason are factually correct.
The reason also provides an apt explanation for the assertion.
Answer:
Assertion is true but reason is flase