Physics Rotational & Circular Motion BUMHS 2024
PMDC Verified Question 23 of 95
Velocity 'v' of an electron revolving around the nucleus is at ____ to the radius r of the orbit.
A
Acute angle
B
Obtuse angle
C
Right angle
D
Supplementary angle
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Right angle
Concept:

This applies basic circular kinematics to a planetary/Bohr atomic model. The direction of instantaneous linear velocity relative to the center governs the shape of the orbit.

Solution:

  • In uniform circular motion, the radius line points from the center strictly outward.
  • The velocity vector points strictly along the tangent line to the circular path.
  • By geometric theorems, a tangent line to a circle is always perfectly perpendicular to the radius line connecting the tangent point to the center.
  • Therefore, the angle between them is exactly \( 90^\circ \), which is a Right angle.


Why other options are incorrect:

  • Option A or Option B would imply the electron is spiraling inward or spiraling outward, escaping the orbit.
  • Option D refers to two angles summing to 180, which doesn't directly describe a single geometric vector intersection.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

Previous Question All Rotational & Circular Motion MCQs Next Question

Want to solve full-length papers under timed exam conditions?

Practice with zero-scroll lockdown sprints, dynamic latency zone timers, live peer selection telemetry, and the automated Amber mistake recovery loop.

Enter Arena Sprint iOS App Android App