Question

A 750-Hz, 20-V source is connected to a resistance of , an inductance of 0.1803 H and a capacitance of , all in series. Calculate the time in which the resistance (thermal capacity = 2 JoC–1) will get heated by 10oC. 

Solution

Correct option is

348 s

The inductive reactance in the circuit is 

       

The capacitive reactance is 

       .  

The impedance of the circuit is 

           

             

The power dissipated is 

         

             

Heat produced in the resistance  

             . Let this heat be produced in time t. then   

         

.

SIMILAR QUESTIONS

Q1

A circuit containing a 80-mH inductor and a 60- capacitor in series is connected to a 230 V-50 Hz supply. The resistance in the circuit is negligible. Obtain the current amplitude and rms current.  

Q2

A series L-C-R circuit having L = 1.5 H,  is connected to a 200-V a.c. supply of variable frequency. When the supply frequency equals the natural frequency of the circuit, find the average power transferred to the circuit in one full cycle. 

Q3

An inductor L, a capacitor of  and the resistor of  are connected in series with an a.c. source of frequency 50 Hz. If the current is in phase with the voltage, calculate the inductance of the inductor.

Q4

A capacitor, a  resistor and a 80-mH inductor are in series with a 50-Hz a.c source. Calculate the capacitance if the current is in phase with the voltage. 

Q5

A series L-C circuit has L = 0.405 H and . The resistance R is zero. Find the frequency of resonance.    

Q6

In a series L-C-R circuit connected to a variable frequency 220-V source; we have : L = 4.0 H, . Calculate the resonant frequency of the circuit.   

Q7

A variable-frequency 230-V alternating voltage source is connected across a series combination of L = 5.0 H,  and . Calculate the angular frequency of the source which drives the circuit in resonance. 

Q8

A series LCR circuit with L = 0.12 H, C = 480 nF and  is connected to a 230-V variable-frequency supply. What is the source frequency for which current a amplitude is maximum? Find this maximum value.

Q9

An L C R circuit has L = 10 mH connected in series to a source of  volt. Calculate the current-amplitude and the average power dissipated per cycle at a frequency 10% lower than the resonant frequency. 

Q10

Obtain the resonant frequency and Q-factor of a series LCR circuit with L= 3.0 H. How will you improve the sharpness of resonance of the circuit by reducing its full width at half maximum by a factor of 2?