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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 2 A in the same resistor?

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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 20
A current in circuit is given by i=3+4sinωt A. Then the effective value of current is (in A) :
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Beta Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise (Conceptual Questions)>Q 21
Incorrect statements are:
a A.C. meters can measure D.C. also.
b If A.C. meter measures D.C. their scale must be linear and uniform.
c A.C. and D.C. meters are based on the heating effect of current.
(d) A.C. meter reads RMS value of current.
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Beta Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise (Conceptual Questions)>Q 23

The relation between an A.C. voltage source and time in SI units is:
V=120sin100πtcos100πt V value of peak voltage and frequency will be respectively- 

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Beta Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise (Conceptual Questions)>Q 24
If an AC main supply is given to be 220 V. What would be the average emf during a positive half-cycle ?
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Beta Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise (Conceptual Questions)>Q 25
The hot wire ammeter measures:
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Beta Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise (Conceptual Questions)>Q 26
Frequency of A.C. in India is,
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Beta Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise (Conceptual Questions)>Q 27
For an alternating current I = I0cos ωt, What is the rms value and peak value of current :- 
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Beta Question Bank for Medical: Physics>Chapter 28 - Alternating Current>Exercise (Conceptual Questions)>Q 28
If a step-up transformer have turn ratio 5, frequency 50 Hz, root-mean-square value of potential difference on primary 100 V and the resistance of the secondary winding is 500 Ω, then the peak value of voltage in secondary winding will be (the efficiency of the transformer is 100%),