In given circuit R = 100 Ω . If voltage leads current by 60 ∘ then find average power.

The voltage across the circuit V = 200 sin 100 π t V and voltage leads the current, current lags by 60 ° . According to the phasor diagram, the phase angle tan ϕ = X L - X C R ⇒ tan 60 ° = X L - X C 100 ⇒ X L - X C = 100 3 Ω The impedance of the circuit Z = R 2 + ( X L - X C ) 2 ⇒ Z = ( 100 ) 2 + ( 100 2 ) 2 ⇒ Z = 200 Ω , The peak voltage V 0 = 200 V , The RMS voltage E RMS = V 0 2 = 200 2 = 100 2 V , The RMS current I RMS = V RMS Z According to the Phasor diagram, Power factor cos ϕ = R Z ⇒ cos ϕ = 100 200 = 1 2 Average Power P avg = E RMS I RMS cos ϕ ⇒ P avg = E RMS 2 Z cos ϕ ⇒ P avg = ( 100 2 ) 2 200 × 1 2 ⇒ P avg = 50 W

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Beta Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise (Conceptual Questions)>Q 12

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A step up transformer has turn ratio 10 : 1. A cell of e.m.f. 2 volts is fed to the primary. Secondary voltage developed is :-

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Important Questions on Alternating Current

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Beta Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise (Conceptual Questions)>Q 13

In given circuit $R = 100 Ω$ . If voltage leads current by $60^{\circ}$ then find average power.

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Beta Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise (Conceptual Questions)>Q 14

An inductor of reactance

4 Ω

and a resistor of resistance

3 Ω

are connected in series with

100 V

ac supply, calculate watt less current in the circuit.

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Beta Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise (Conceptual Questions)>Q 15

A

100 Ω

resistor is connected to a

220 V, 50 Hz

ac supply. What is the rms value of current

(A)

in the circuit?

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Beta Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise (Conceptual Questions)>Q 16

A

100 Ω

resistor is connected to

220 V

,

50 Hz

ac supply, what is the net power consumed over a full cycle?

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Beta Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise (Conceptual Questions)>Q 17

A choke coil and a resistance are connected in series in an a.c. circuit and potential of

130 V

is applied to the circuit. If the potential across the resistance is

50 V

. What would be the potential difference across the choke coil?

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Beta Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise (Conceptual Questions)>Q 18

What is the rms value of an alternating current which when passed through a resistor, produces heat which is thrice of that produced by a direct current of