Difficulty: Easy
Correct Answer: 90°
Explanation:
Introduction:
Phase angle descriptions help locate key points on a sinusoid. Knowing where maxima and minima occur is essential for phasor analysis, AC power, and signal timing in communication systems.
Given Data / Assumptions:
Concept / Approach:
The sine function attains its maximum value +1 at θ = 90°. Therefore the waveform’s maximum positive amplitude occurs at 90°. At 270° (or −90°), the sine reaches −1 (negative peak). At 0° and 180°, the waveform crosses zero and reaches zero, respectively, but not the maximum.
Step-by-Step Solution:
Verification / Alternative check:
Graph of a sine wave or unit-circle evaluation confirms that the peak positive amplitude is at 90°. A derivative check shows dv/dθ = Vm * cos(θ) = 0 at 90°, indicating an extremum; second derivative test confirms it is a maximum.
Why Other Options Are Wrong:
Common Pitfalls:
Final Answer:
90°
Discussion & Comments