Power in an AC Circuit

Q.

What is the power factor of RLC circuit?

Q.

Is power the same in series and parallel?

Q. A choke coil is preferred to a rheostat in ac circuit as

1. It consumes almost zero power
2. It increases current
3. It increases power
4. It increases voltage

Q. The average power dissipated in a pure inductor of inductance L when an ac current is passing through it, is

1. $\frac{1}{2}L{I}^2$
2. $\frac{1}{4}L{I}^2$
3. $2L{I}^2$
4. $Zero$

Q. An LCR series circuit with a resistance of 100 ohm is connected to an ac source of 100 V (r.m.s.) and angular frequency 300 rad/s. When only the capacitor is removed, the current lags behind the voltage by . When only the inductor is removed the current leads the voltage by . The average power dissipated is

1. 50 W
2. 100 W
3. 200 W
4. 400 W

Q. A direct current of 2A and alternating current having a maximum value of 2A flow through two identical resistance. The ratio of heat produced in the two resistance will be:

1. 1 : 1
2. 1 : 2
3. 2 : 1
4. 4 : 1

Q. An ac supply gives 30 V r.m.s. which passes through a $10\Omega$ resistance. The power dissipated in it is

1. $90\sqrt{2}W$
2. $90W$
3. $45\sqrt{2}W$
   
4. $45W$

Q. An AC source rated $100\text{V (rms)}$ supplies a current of $10\text{A (rms)}$ to a circuit. The average power delivered by the source

1. Must be $1000\text{W}$
2. May be $1000\text{W}$
3. May be greater than 1000 W
4. May be less than 1000 W

Q. An ac supply gives 30 V r.m.s. which passes through a $10\Omega$ resistance. The power dissipated in it is

1. $90\sqrt{2}W$
2. $90W$
3. $45\sqrt{2}W$
   
4. $45W$

Q. Two cities 150km apart. Electric power is sent one city to another city through copper wire. The fall potential per km is 8 volt and the average resistance per km is 0.5 ohm. The power loss in the wire is?