Physics Alternating Current PMDC Conceptual Practice
PMDC Verified Question 60 of 127
When an alternating voltage is applied across a pure inductor, the voltage across the inductor leads the current by an angle of:
A
\(0\text{ rad}\)
B
\(\pi\text{ rad}\)
C
\(\frac{\pi}{4}\text{ rad}\)
D
\(\frac{\pi}{2}\text{ rad}\)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: \(\frac{\pi}{2}\text{ rad}\)
Concept:

The self-induced back emf in an inductor reaches its peak \(90^\circ\) (\(\pi/2\text{ radians}\)) before the current reaches its peak.

Formula / Reaction:

$$\phi = +\frac{\pi}{2}\text{ radians} = +90^\circ$$

Solution:

  • Induced voltage is proportional to \(di/dt\), which leads \(i(t)\) by \(\pi/2\text{ rad}\).


Why other options are incorrect:

  • Opt_A: Phase angle for a pure resistor.


  • Opt_B: Phase inversion (\(180^\circ\)).


  • Opt_C: \(45^\circ\) phase angle in mixed circuits.

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 Alternating Current 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