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(A): A bar magnet is dropped into a long...

(A): A bar magnet is dropped into a long vertical copper tube. Even taking air resistance as negligible, the magnet attains a constant terminal velocity. If the tube is heated, the terminal velocity gets increased.
(R) : The terminal velocity depends on eddy current produced in bar magnet.

A

Both .A. and .R. are true and .R. is the correct explanation of .A.

B

Both .A. and .R. are true and .R. is not the correct explanation of .A.

C

.A. is true and .R. is false

D

.A. is false and .R. is true

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question, we need to analyze both the assertion (A) and the reason (R) provided, and determine their truth values and whether R correctly explains A. ### Step-by-Step Solution: 1. **Understanding the Assertion (A)**: - The assertion states that a bar magnet dropped into a long vertical copper tube attains a constant terminal velocity, even when air resistance is negligible. This is true because as the magnet falls, it induces eddy currents in the copper tube due to the changing magnetic field. 2. **Understanding the Reason (R)**: - The reason states that the terminal velocity depends on the eddy currents produced by the bar magnet. This is also true. The eddy currents create a magnetic field that opposes the motion of the magnet (according to Lenz's Law), which results in a drag force that eventually balances the gravitational force acting on the magnet, leading to terminal velocity. 3. **Effect of Heating the Tube**: - When the copper tube is heated, its resistance decreases. This means that the eddy currents generated by the falling magnet will be stronger (since they are inversely proportional to resistance). As a result, the opposing force on the magnet will be greater, allowing the magnet to fall faster, thus increasing the terminal velocity. 4. **Determining the Relationship**: - While both statements are true, the reason (R) does not provide a complete explanation for the assertion (A). The assertion discusses the terminal velocity attained by the magnet, while the reason focuses on the dependence of terminal velocity on eddy currents without addressing how heating the tube affects these currents and consequently the terminal velocity. 5. **Conclusion**: - Therefore, both A and R are true, but R is not the correct explanation of A. ### Final Answer: - Both A and R are true, but R is not the correct explanation of A.
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