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Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A : If Oxygen ion (O−2) and Hydrogen ion (H+) enter normal to the magnetic field with equal momentum, then the path of O−2 ion has a smaller curvature than that of H+. Reason R : A proton with same linear momentum will form a path of smaller radius of curvature on entering a uniform magnetic field perpendicularly. In the light of the above statements, choose the correct answer from the options given below

1. (1) A is true but R is false
2. (2) Both A and R are true and R is the correct explanation of A
3. (3) Both A and R are true but R is NOT the correct explanation of A
4. (4) A is false but R is true

Correct answer: (1) A is true but R is false

Solution

Assertion A is correct because the curvature of the path of an ion in a magnetic field is inversely proportional to its mass; since O−2 is heavier than H+, it will have a larger radius of curvature. However, Reason R is incorrect because it incorrectly generalizes the behavior of protons without considering the mass difference between ions, which affects their path curvature.

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