Math Problem Statement

You are testing the voltage across a capacitor in an AC circuit. The instrument you are using indicates this voltage to have a magnitude of 100 V and a phase angle of 45 degrees. Convert this voltage into a complex number.

Solution

To convert the voltage with a magnitude of 100V100 \, \text{V} and a phase angle of 4545^\circ into a complex number, we can express it in the form:

V=Vmagnitude(cos(θ)+isin(θ))V = V_{\text{magnitude}} \cdot (\cos(\theta) + i \sin(\theta))

where:

  • Vmagnitude=100VV_{\text{magnitude}} = 100 \, \text{V}
  • θ=45\theta = 45^\circ

Steps:

  1. Calculate the Real Part: Real part=100cos(45)=10022=1000.7071=70.71\text{Real part} = 100 \cdot \cos(45^\circ) = 100 \cdot \frac{\sqrt{2}}{2} = 100 \cdot 0.7071 = 70.71

  2. Calculate the Imaginary Part: Imaginary part=100sin(45)=10022=1000.7071=70.71\text{Imaginary part} = 100 \cdot \sin(45^\circ) = 100 \cdot \frac{\sqrt{2}}{2} = 100 \cdot 0.7071 = 70.71

Thus, the voltage in complex form is:

V=70.71+70.71iVV = 70.71 + 70.71i \, \text{V}

or, in polar form:

V=10045V = 100 \angle 45^\circ

Would you like further details on complex conversions, or do you have any other questions?

Here are five related questions to explore further:

  1. How do you convert a complex number in rectangular form back to polar form?
  2. What is the significance of phase angles in AC circuits?
  3. How would you interpret this voltage in terms of sinusoidal waveforms?
  4. What role does the capacitor play in affecting phase angles in AC circuits?
  5. How do impedance and phase angle relate in an AC circuit with capacitive elements?

Tip: Remember, for phase angles, converting degrees to radians (or vice versa) may be necessary, especially in calculations involving trigonometric functions in different contexts.

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Math Problem Analysis

Mathematical Concepts

Complex Numbers
Trigonometry
AC Circuit Analysis

Formulas

V = V_magnitude * (cos(θ) + i * sin(θ))
cos(45°) = √2 / 2
sin(45°) = √2 / 2

Theorems

Euler's formula for complex numbers

Suitable Grade Level

Grades 11-12