Sinusoidal AC

Q. The voltage of an ac supply varies with time (t) as $V=120sin100\pi tcos100\pi t$. The maximum voltage and frequency respectively are

1. 120 volts, 100 Hz
2. $\frac{120}{\sqrt{2}}volts,100Hz$
3. 60 volts, 200 Hz
4. 60 volts, 100 Hz

Q. The equation of an alternating voltage is V =100 sin 100 $\pi$ t volt. Its peak value and frequency are

1. 100 V, 50 Hz
2. 50V, 100Hz
3. 200 V, 100 Hz
4. 100 V, 200 Hz

Q. Match the following
$\begin{array}{cc}Currents& r.m.svalues\\ \left(1\right)x_{0}sin\omega t& \left(i\right)x_0\\ \left(2\right)x_{0}sin\omega tcos\omega t& \left(ii\right)\frac{x_0}{\sqrt{2}}\\ \left(3\right)x_{0}sin\omega t+x_{0}cos\omega t& \left(iii\right)\frac{x_0}{\left(2\sqrt{2}\right)}\end{array}$

1. 1. (i), 2. (ii), 3. (iii)
2. 1. (ii), 2. (iii), 3. (i)
3. 1. (i), 2. (iii), 3. (ii)
4. None of these

Q. The voltage of an ac supply varies with time (t) as $V=120sin100\pi tcos100\pi t$. The maximum voltage and frequency respectively are

1. 120 volts, 100 Hz
2. $\frac{120}{\sqrt{2}}volts,100Hz$
3. 60 volts, 200 Hz
4. 60 volts, 100 Hz

Q. The voltage of an ac source varies with time according to the equation $V=100sin100\pi tcos100\pi t$ where t is in seconds and V is in volts. Then

1. The peak voltage of the source is 100 volts
2. The peak voltage of the source is 50 volts
3. The peak voltage of the source is $\frac{100}{\sqrt{2}}$ volts
4. The frequency of the source is 50 Hz

Q. An ac voltage is represented by $E=220\sqrt{2}cos\left(50\pi \right)t$. The current becomes zero times in 1 sec.

1. 25
2. 50
3. 75
4. 100

Q. The voltage of an ac source varies with time according to the equation V = 200sin$\left(100\pi t\right).cos\left(100\pi t\right)$ where t is in seconds and V is in volts. Then

1. The peak voltage of the source is 100 volts
2. The peak voltage of the source is 50 volts
3. The peak voltage of the source is $\frac{100}{\sqrt{2}}$ volts
4. The frequency of the source is 50 Hz

Q.

An ac voltage is represented by $E=220\sqrt{2}cos\left(50\pi \right)t$ How many times will the current becomes zero in 1 s?

1. 50 times

2. 100 times

3. 30 times

4. 25 times

Q. The peak value of an alternating emf is given by $E=E_{0}cos\left(wt\right)$ is 10 volt and its frequency is 50 Hz. At a time $t=\left(\frac{1}{600}\right)$ second, the instantaneous value of the emf is:

1. 1V
2. 5V
3. $5\sqrt{3}V$
4. 10V

Q. The equation of an alternating voltage is V =100 sin 100 $\pi$ t volt. Its peak value and frequency are

1. 100 V, 50 Hz
2. 50V, 100Hz
3. 200 V, 100 Hz
4. 100 V, 200 Hz