CHAPTER-5, ALTERNATING CURRENT CIRCUITS

1. The power factor varies between

 
 
 
 

2. If R, C and L be the resistance, capacitance and inductance in a circuit in which ac of frequency f is set up, then which of the following has the dimensions of R ?

 
 
 
 

3. A capacitor of capacitance 1 µ F and a resistor of resistance 105 ohm are connected in series with a battery of e.m.f. 100 volt and negligible internal resistance. Then the time constant of the circuit is

 
 
 
 

4. For long distance transmission, the ac is stepped up because transmission at high voltage is

 
 
 
 

5. Which of the following decreases the efficiency of the transformer ?

 
 
 
 

6. In a series resonant circuit the ac voltages across resistance R, inductance L and capacitance C are 5V, 10V and 10V respectively. The ac voltage applied to the circuit will be

 
 
 
 

7. The impedance of a 10 microfarad capacitor for 50 Hz ac is

 
 
 
 

8. The inductance of a coil is 5 H. What is its effective reactance in dc circuit ?

 
 
 
 

9. Large value of which of the following does not allow electrical oscillations in the LCR circuit.

 
 
 
 

10. Which of the following helps in the operation of the choke coil ?

 
 
 
 

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