Entry Test MCQ :: Alternating Current

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31.

A choke is used as a resistance in

A.	DC circuit	B.	AC circuits
C.	Both AC and DC circuit	D.	Full wave rectifier circuit

32.

At resonance the value of the power factor in an L-C-R series circuit is

A.	Zero
C.	1	D.	not definite

33.

An A.C series circuit containing 4? resistance and 3-? inductive reactance. The impedance of the circuit is

A.	1?	B.	5?
C.	7?	D.	7/?2?

34.

An inductive coil has a resistance of 100?. When an AC signal of frequency 1000Hz is fed to the coil the applied voltage leads the current by 45?. What is the inductance of the coil?

A.	10mH	B.	12mH
C.	16mH	D.	20mH

35.

Choose the correct statement. In the case of AC circuit ohms law holds for

A.	Peak values of voltage and current	B.	Effective values of voltage and current
C.	Instantaneous values of voltage and current	D.	All of the above

36.

The phase angle between the voltage and the current in an AC circuit consisting of a resistance is

A.	Zero	B.	45?
C.	90?	D.	180?

37.

In an LCR series circuit, if V is the effective value of the applied voltage VR is the voltage across R VL is the effective voltage across L & Vc is the effective voltage across C then

A.	V = VR+VL+VC	B.	V2 = VR2+VL2+VC2
C.	V2 = VR2+(VL-VC)2	D.	V2 = VL2+(VR-VC)2

38.

a voltage V = V? cos ?t is applied across a resistor of resistance R the average power dissipated per cycle in the resistor is given by

A.	V?/?2R	B.	V?/?2?R
C.	V?2/?2R	D.	V?2/?2?R

39.

Two identical coaxial circular loops carry equal currents in the same direction. If the loops approach each other the current in

A.	Each increases	B.	Each decreases
C.	Each remains the same	D.	One increases whereas that in the other decreases

40.

An inductor may store energy in

A.	its electric field	B.	its coils
C.	its magnetic field	D.	both electric and magnetic fields