Difficulty: Easy
Correct Answer: (A) is true, but (R) is false.
Explanation:
Introduction / Context:We test a physical fact about magnetism against an irrelevant cosmetic reason.
Given Data / Assumptions:
Concept / Approach:Magnetic alignment is due to torque on a magnetic dipole in Earth’s magnetic field; paint color is irrelevant.
Step-by-Step Solution:
1) (A) True in principle (allowing for local declination/variation).2) (R) False: red paint is a convention to mark the north-seeking end; it does not cause alignment.3) Hence (R) cannot explain (A).Verification / Alternative check:Unpainted but magnetized needles still align; painted but unmagnetized ones do not.
Why Other Options Are Wrong:(a)/(b) require (R) true; (d)/(e) misstate (A).
Common Pitfalls:Confusing indicators (paint) with causes (magnetism).
Final Answer:Option C: (A) true, (R) false.
Discussion & Comments