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The voltage over a cycle varies as V=V...

The voltage over a cycle varies as
`V=V_(0)sin omega t` for `0 le t le (pi)/(omega)`
`=-V_(0)sin omega t` for `(pi)/(omega)le t le (2pi)/(omega)`
The average value of the voltage one cycle is

A

`(V_(0))/(sqrt2)`

B

`((2)/(pi))V_(0)`

C

`((2)/(pi))V_(0)`

D

ZERO

Text Solution

AI Generated Solution

The correct Answer is:
To find the average value of the voltage over one cycle, we can follow these steps: ### Step 1: Define the average voltage formula The average value of a function \( V(t) \) over a time period \( T \) is given by the formula: \[ V_{\text{avg}} = \frac{1}{T} \int_0^T V(t) \, dt \] In our case, the time period \( T \) for one complete cycle is \( T = \frac{2\pi}{\omega} \). ### Step 2: Break the integral into two parts The voltage function \( V(t) \) is defined in two parts: 1. For \( 0 \leq t \leq \frac{\pi}{\omega} \): \[ V(t) = V_0 \sin(\omega t) \] 2. For \( \frac{\pi}{\omega} < t \leq \frac{2\pi}{\omega} \): \[ V(t) = -V_0 \sin(\omega t) \] Thus, we can express the average voltage as: \[ V_{\text{avg}} = \frac{1}{T} \left( \int_0^{\frac{\pi}{\omega}} V_0 \sin(\omega t) \, dt + \int_{\frac{\pi}{\omega}}^{\frac{2\pi}{\omega}} -V_0 \sin(\omega t) \, dt \right) \] ### Step 3: Calculate the first integral Calculate the integral from \( 0 \) to \( \frac{\pi}{\omega} \): \[ \int_0^{\frac{\pi}{\omega}} V_0 \sin(\omega t) \, dt \] Using the integral of sine: \[ \int \sin(x) \, dx = -\cos(x) \] We have: \[ \int_0^{\frac{\pi}{\omega}} V_0 \sin(\omega t) \, dt = V_0 \left[ -\frac{1}{\omega} \cos(\omega t) \right]_0^{\frac{\pi}{\omega}} = V_0 \left( -\frac{1}{\omega} \left( -1 - 1 \right) \right) = \frac{2V_0}{\omega} \] ### Step 4: Calculate the second integral Now calculate the integral from \( \frac{\pi}{\omega} \) to \( \frac{2\pi}{\omega} \): \[ \int_{\frac{\pi}{\omega}}^{\frac{2\pi}{\omega}} -V_0 \sin(\omega t) \, dt \] Using the same integration method: \[ \int_{\frac{\pi}{\omega}}^{\frac{2\pi}{\omega}} -V_0 \sin(\omega t) \, dt = -V_0 \left[ -\frac{1}{\omega} \cos(\omega t) \right]_{\frac{\pi}{\omega}}^{\frac{2\pi}{\omega}} = -V_0 \left( -\frac{1}{\omega} (1 - (-1)) \right) = -V_0 \left( -\frac{2}{\omega} \right) = \frac{2V_0}{\omega} \] ### Step 5: Combine the results Now substitute the results of the two integrals back into the average voltage formula: \[ V_{\text{avg}} = \frac{1}{\frac{2\pi}{\omega}} \left( \frac{2V_0}{\omega} + \frac{2V_0}{\omega} \right) = \frac{1}{\frac{2\pi}{\omega}} \left( \frac{4V_0}{\omega} \right) = \frac{4V_0}{2\pi} = \frac{2V_0}{\pi} \] ### Final Answer The average value of the voltage over one cycle is: \[ V_{\text{avg}} = \frac{2V_0}{\pi} \]
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