Question

An emf E = 100 sin 314t volt is applied across a pure capacitor of 637 . Find the instantaneous current i.

Solution

Correct option is

20 cos 314t

               .  

In a pure capacitor the current leads the voltage by 90o. Therefore, the instantaneous current is given by  

              

                  

.      

  

               

Substituting this value of i0 in eq. (i), we get  

          .

SIMILAR QUESTIONS

Q1

In a dynamo, a coil of area 0.2 m2 and having 100 turns rotates in a magnetic field of 0.1 Wb m–2 with an angular velocity of 100 rad s–1. The output terminals are connected through a resistance of . Calculate the torque , as a function of time t, required to keep the coil rotating.

Q2

The electric main in a house is marked 220V-50Hz. Write down the equation for instantaneous voltage.

Q3

A sinusoidal voltage V = 200 sin 314t is applied to a  resistor. Find the frequency of the supply.

Q4

In an a.c. circuit the peak voltage of supply is 300 V. What is rms voltage? What is mean voltage during a positive half-cycle and for a complete cycle?

Q5

 resistor is connected to 220 V-50 Hz a.c. supply. Find rms value of current in the circuit and the net power consumed for a complete cycle.

Q6

A 220 V-50 Hz a.c. supply is applied to a 44-mH inductor. What is rmscurrent in the circuit? What is the net power absorbed over a complete cycle?

Q7

A 110 V-60 Hz a.c. supply is applied to a  capacitor. What is rms current in the circuit? What is the net power absorbed over a complete cycle?

Q8

An alternating voltage E = 200 sin 300t is applied across a series combination of  and L = 800 mH. Calculate the impedance of the circuit.

Q9

A coil of inductance 0.50 H and resistance  is connected to a 240 V-50 Hz a.c. supply. What are the maximum current in the coil and the time lag between voltage maximum and current maximum?

Q10

An a.c. voltage V = 200 sin 314t is applied across a series C-R circuit.Where . Find the capacitive reactance.