Subelement B: Electrical Math— Topic 12: Waveforms
Question 3-12B3
Element 3 (GROL)At 240 degrees, what is the amplitude of a sine-wave having a peak value of 5 volts?
Explanation
The instantaneous amplitude of a sine wave at any given phase angle can be calculated using the formula: Amplitude = Peak Value × sin(angle).
In this case, the peak value is 5 volts and the angle is 240 degrees.
Amplitude = 5V × sin(240°)
The sine of 240 degrees is -0.866 (since 240 degrees is in the third quadrant, where sine values are negative, and sin(240°) = sin(180° + 60°) = -sin(60°)).
Amplitude = 5V × (-0.866)
Amplitude = -4.33 volts.
Therefore, the amplitude at 240 degrees is approximately -4.3 volts.
Option B (-2.5 volts) would correspond to an angle where sin(angle) = -0.5, or if you mistakenly used cosine. Options C (+2.5 volts) and D (+4.3 volts) are incorrect because the sine wave is in a negative phase at 240 degrees.
Related Questions
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