Alpha Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise-3>Q 2

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The $R M S$ value of potential difference $V$ shown in the figure is:

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Important Questions on Alternating Current

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Alpha Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise-3>Q 3

A coil has resistance

30 ohm

and inductive reactance

20 ohm

at

50 Hz

frequency. If an ac source, of

200 V

,

100 Hz

, is connected across the coil, the current in the coil will be ?

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Alpha Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise-3>Q 4

In an electrical circuit

R, L, C

and an a.c. voltage source are all connected in series. When

L

is removed from the circuit, the phase difference between the voltage the current in the circuit is

π / 3 .

If instead,

C

is removed from the circuit, the phase difference is again

π / 3 .

The power factor of the circuit is ?

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Alpha Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise-3>Q 5

The instantaneous values of alternating current and voltages in a circuit are given as

$\begin{array}{l} i = \frac{1}{\sqrt{2}} (\sin 100 π t) ampere \\ e = \frac{1}{\sqrt{2}} \sin (100 π t + \frac{π}{3}) Volt \end{array}$

The average power in Watts consumed in the circuit is:

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Alpha Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise-3>Q 6

A coil of self-inductance

L

is connected in series with a bulb

B

and an

A C

source. Brightness of the bulb decreases when

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Alpha Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise-3>Q 7

A resistance

R

draws power

P

when connected to an

AC

source. If an inductance is now placed in series with the resistance, such that the impedance of the circuit becomes

Z

, the power drawn will be:

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Alpha Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise-3>Q 8

An inductor

20 mH

a capacitor

50 μF

and a resistor

40 Ω

are connected in series across a source of emf

V = 10 \sin 340 t

. The power loss in A.C. circuit is

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Alpha Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise-3>Q 9

A small signal voltage

V (t) = V_{0} \sin ω t

is applied across an ideal capacitor

C

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Alpha Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise-3>Q 10

Which of the following combinations should be selected for better tuning of an

L C R

circuit used for communication