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An alternating current is given by $i = i_{1} \sin ω t + i_{2} \cos ω t$ . The RMS current is given by

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Important Questions on Alternating Current

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Voltage Applied to a Resistor

For an

AC

given by

I = 50 \cos (100 t + 45 °) A

. The value of

I_{rms} =_________A

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Voltage Applied to a Resistor

An alternating current is given by the equation

i = i_{1} \sin ω t + i_{2} \cos ω t

. The rms current will be:

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Voltage Applied to a Resistor

A C

source rated

220 V, 50 Hz

is connected to a resistor. The time taken by the current to change from its maximum to the rms value is :

HARD

Physics>Electricity and Magnetism>Alternating Current>AC Voltage Applied to a Resistor

10 Ω

resistance is connected across

220 V - 50 Hz

AC supply. The time taken by the current to change from its maximum value to the

rms

value is:

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Voltage Applied to a Resistor

The RMS value of emf given by

E = (8 \sin ω t + 6 \cos ω t)

volt is

MEDIUM

Physics>Electricity and Magnetism>Alternating Current>AC Voltage Applied to a Resistor

A pure inductor of inductance

0.1 H

is connected to an AC source (of rms voltage)

220 V

angular frequency of

300 Hz .

The rms current is

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Voltage Applied to a Resistor

A C

current is given by

I = I_{1} s i n ω t + I_{2} c o s ω t .

A hot wire ammeter will give a reading:

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Voltage Applied to a Resistor

An alternating current is given by

i = 2 \sin ω t + 6 \cos ω t .

The R.M.S. current in amperes is,

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Voltage Applied to a Resistor

An AC source is rated at

220 V, 50 Hz

. The time taken for voltage to change from its peak value to zero is

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Voltage Applied to a Resistor

The rms value of potential difference $V_{0}$ shown in figure is

Question Image

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Voltage Applied to a Resistor

If the mains voltage is

230 V

, then the peak voltage approximately is

MEDIUM

Physics>Electricity and Magnetism>Alternating Current>AC Voltage Applied to a Resistor

40 μF

capacitor is connected to a

200 V

50 Hz

AC supply. The rms value of the current in the circuit is, nearly:

MEDIUM

Physics>Electricity and Magnetism>Alternating Current>AC Voltage Applied to a Resistor

The alternating current is given by, $i = \{\sqrt{42} \sin (\frac{2 π}{T} t) + 10\} A$ . The R.M.S. value of this current is __________ $A$ .

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Voltage Applied to a Resistor

A . C .

voltage

V = 5 \cos (1000 t) V

is applied to a

L - R

series circuit of inductance

3 mH

and resistance

4 Ω .

The value of maximum current in the circuit is _____

A

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Voltage Applied to a Resistor

A bulb of resistance

280 Ω

is supplied with a

200 V

A C

supply. What is the peak current?

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Voltage Applied to a Resistor

The alternating current in a circuit is given by the equation $i = 10 \sin (100 πt + \frac{π}{6})$ . The current attains its first maximum at $t$ is:

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Voltage Applied to a Resistor

A resistance of

20 Ω

is connected to an alternating current source of

110 V

. If the frequency of the A.C. source is

50 Hz

, then the time taken by the current to change from its maximum value to the R.M.S. value is

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Voltage Applied to a Resistor

The mean or average value of AC over a complete cycle is

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Voltage Applied to a Resistor

In the given circuit the peak voltages across $C, L$ and $R$ are $30 V, 110 V$ and $60 V$ respectively. The rms value of the applied voltage is

Question Image

HARD

Physics>Electricity and Magnetism>Alternating Current>AC Voltage Applied to a Resistor

The instantaneous voltages at three terminals marked

X, Y

and

Z

are given by

V_{X} = V_{0} \sin ω t

V_{Y} = V_{0} \sin (ω t + \frac{2 π}{3})

and

V_{Z} = V_{0} \sin (ω t + \frac{4 π}{3}) .

An ideal voltmeter is configured to read rms value of the potential difference between its terminals. It is connected between points

X

and

Y

and then between

Y

and

Z

. The reading(s) of the voltmeter will be

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

Important Questions on Alternating Current

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An alternating current is given by $i = i_{1} \sin ω t + i_{2} \cos ω t$ . The RMS current is given by