MCQs of Alternating Current

Alternating Current MCQs

MCQs of Alternating Current

Showing 91 to 100 out of 168 Questions

91.

A 10 Ω resistance, 5mH inductor and 10μF capacitor are joined in series. When a suitable frequency if alternating current source is joined to this combination, the circuit resonates. If the resistance is halved, the resonance frequency _____

(a)	is halved
(b)	is doubled
(c)	remains unchanged
(d)	in quadrupled

92.

L, C and R represent physical quantities inductance, capacitance and resistance respectively. What is the combination representing dimension of frequency ?

(a)	LC
(b)	${(LC)}^{- \frac{1}{2}}$
(c)	${(\frac{L}{C})}^{- \frac{1}{2}}$
(d)	$\frac{C}{L}$

93.

An emf E = 4 cos (1000t) volt is applied to an LR circuit of inductance 3 mH and resistance 4 Ω. What is the amplitude of current in the circuit ?

(a)	$\frac{4}{\sqrt{7}} A$
(b)	1.0 A
(c)	$\frac{4}{7} A$
(d)	0.8 A

94.

In an A.C. circuit, a resistance of R Ω is connected in series with an inductance L. If phase angle between voltage and current be 45°. Then what will be the value of inductive reactance ?

(a)	$\frac{R}{4}$
(b)	$\frac{R}{2}$
(c)	R
(d)	can not be found with given data.

95.

In an A.C. series circuit, the instantaneous current is maximum when the instantaneous voltage is maximum. What will be the circuit element connected to the source ?

(a)	Pure inductor
(b)	Pure capacitor
(c)	Pure resistor
(d)	Combination of capacitor and an inductor

96.

If 8Ω resistance and 6Ω reactance are present in an A.C. series circuit then what will be the impedence of the circuit ?

(a)	20 Ω
(b)	5 Ω
(c)	10 Ω
(d)	$14 \sqrt{2} Ω$

97.

A 220 V, 50 Hz a.c. source is connected to an inductance of 0.2 H and a resistance of 20 Ω in series. What is the current in the circuit ?

(a)	10 A
(b)	5 A
(c)	33.3 A
(d)	3.33 A

98.

In an A.C. circuit the reactance of a coil is

\sqrt{3}

times than its resistance, the phase difference between the voltage and the current across the coil will be _____

(a)	$\frac{π}{3}$
(b)	$\frac{π}{2}$
(c)	$\frac{π}{4}$
(d)	$\frac{π}{6}$

99.

The capacity of a pure capacitor is 1 faraday in D.C. circuits, then what will be its effective resistance ?

(a)	Zero
(b)	Infinite
(c)	1 Ω
(d)	$\frac{1}{2}$

100.

The inductive reactance of an inductor of

\frac{1}{π}

henry at 50 Hz frequency is _____

(a)	$\frac{50}{π} ohm$
(b)	$\frac{π}{50} ohm$
(c)	100 ohm
(d)	50 ohm

Showing 91 to 100 out of 168 Questions