Alternating Current

IMPORTANT

Alternating Current: Overview

This topic covers concepts, such as, Alternating Current,Alternating Voltage,AC Circuit etc.

Important Questions on Alternating Current

EASY
IMPORTANT

A 15.0 μF  capacitor is connected to 220 V, 50 Hz source. The capacitive reactance and the RMS current would be:

EASY
IMPORTANT

The instantaneous current and voltage of an AC circuit are given by i=10sin314t A and V=100sin314t V. The power dissipation in the circuit is

HARD
IMPORTANT

A resistor of   200 Ω  and a capacitor of 15.0 μF  are connected in series to a 220 V, 50 Hz a.c. source. Calculate

​(i) The current in the circuit.

(ii) The rms voltage across the resistor and the capacitor.

EASY
IMPORTANT

A standard filament lamp consumes 100 W when connected to 200 V ac mains supply. Calculate the peak current through the bulb.

EASY
IMPORTANT

In the given AC circuit, find maximum current through the capacitor

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EASY
IMPORTANT

The RMS value of the time varying current i= I0e-t from 0 to 1 s is

EASY
IMPORTANT

Find the rms and average value of I=10+ 5cos(314t)

HARD
IMPORTANT

A modulating signal 2 sin (6.28 × 106) t is added to the carrier signal
4 sin(12.56 × 109) t for amplitude modulation. The combined signal is passed through a non-linear square law device. The output is then passed through a band pass filter. The bandwidth of the output signal of band pass filter will be MHz.

MEDIUM
IMPORTANT

If I = 2t, then the R.M.S. value of current from 0 to  2 seconds is
 

EASY
IMPORTANT

Given below are two statements:

Statement-I: In an ac circuit, the current through a capacitor leads the voltage across it.

Statement-II: In a.c. circuits containing pure capacitance only, the phase difference between the current and the voltage is π

In the light of the above statements, choose the most appropriate answer from the options given below:

HARD
IMPORTANT

In an AC circuit, the current I is given by the equation i=2 13 sin(50π t ) A. Calculate the time taken to reach from zero to first maximum value.

MEDIUM
IMPORTANT

Calculate the RMS value of the emf for a cycle, whose time variation is shown in figure.

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EASY
IMPORTANT

The variation of the instantaneous current I and the instantaneous emf E in a circuit are shown in the figure. Which of the following statements is correct?

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EASY
IMPORTANT

An alternating current is given by i=i1sinωt+i2cosωt. The RMS current is given by

EASY
IMPORTANT

The INCORRECT statement is.

EASY
IMPORTANT

A resistance of 40Ω is connected to a source of alternating current rated 220 V,50 Hz. Find the time taken by the current to change from its maximum value to the rms value

EASY
IMPORTANT

If E=500sin(100πt) Volt, then the time taken to reach the maximum point from zero.

EASY
IMPORTANT

A 50 μF capacitor is connected to a 110 V,60 Hz ac supply. Determine the rms value of the current in the circuit.

EASY
IMPORTANT

The mean value of current I=I0cosωt from t=0 to t=πω is

MEDIUM
IMPORTANT

How does the rms voltage of AC is related to the peak value of AC voltage?