Question

when charged particles enter earths magnetic field, they experience a deflecting force that curves their trajectories. heavier cosmic ray particles such as iron and nickel nuclei would therefore be expected to deviate more from a straight path than lighter particles like protons, since their greater mass implies greater momentum and thus a larger deflecting force. using simulations to track cosmic ray trajectories in earths atmosphere, researchers found that heavier nuclei did indeed show greater deviations than lighter particles. however, they also observed that protons and alpha particles—which differ substantially in mass—exhibited nearly identical deviations under relativistic conditions. the researchers concluded that this pattern indicates ____ 14 mark for review which choice most logically completes the text? a both mass number and atomic number influence trajectory deviation, and the similar behavior of protons and alpha particles reflects their shared mass - to - charge ratio despite different individual masses b both mass number and atomic number influence trajectory deviation, and the similar behavior of protons and alpha particles reflects their shared atomic number despite different individual masses c mass alone governs trajectory deviation, so the matching deviations of protons and alpha particles must stem from measurement artifacts rather than any genuine physical similarity d mass alone governs trajectory deviation, so the matching deviations of protons and alpha particles must stem from relativistic effects that coincidentally equalize their effective masses

Explanation:

1. Analyze the context: The text first says mass (momentum) affects deviation (heavier nuclei deviate more), but then protons and alpha particles (different masses) have similar deviations under relativistic conditions. We need to find the logical conclusion.
2. Evaluate Option A: It states both mass number (related to mass) and atomic number (related to charge) influence deviation, and protons/alpha particles have the same mass - to - charge ratio (proton: mass = 1, charge = 1; alpha particle: mass = 4, charge = 2, so mass - to - charge ratio is 1 for both). This explains why different masses can have similar deviations (because mass - to - charge ratio is same), and also aligns with the initial idea that mass (mass number) matters (heavier nuclei deviate more).
3. Evaluate Option B: Atomic number of proton is 1, alpha particle is 2. They don't have the same atomic number, so this is incorrect.
4. Evaluate Option C: The text shows that mass alone does not govern deviation (since protons and alpha particles with different masses have similar deviations), so this is wrong.
5. Evaluate Option D: The text's conclusion is about what the pattern indicates about the factors (mass and charge), not about relativistic effects equalizing effective masses. The pattern is used to conclude about the influencing factors, not to explain the deviation as a result of relativistic mass equalization.

Answer:

A. both mass number and atomic number influence trajectory deviation, and the similar behavior of protons and alpha particles reflects their shared mass - to - charge ratio despite different individual masses