A resistance of 20 ohms is connected to a source of an alternating potential $V=220\mathrm{sin}\left(100\pi t\right)$. The time taken by the current to change from its peak value to r.m.s value is

(1) 0.2 sec

(2) 0.25 sec

(3) 25 × 10–3 sec

(4) 2.5 × 10–3 sec

Concept Questions :-

Different types of AC Circuits
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Voltage and current in an ac circuit are given by $V=5\mathrm{sin}\text{\hspace{0.17em}}\left(100\pi t-\frac{\pi }{6}\right)$ and $I=4\mathrm{sin}\text{\hspace{0.17em}}\left(100\pi t+\frac{\pi }{6}\right)$

(1) Voltage leads the current by 30°

(2) Current leads the voltage by 30°

(3) Current leads the voltage by 60°

(4) Voltage leads the current by 60°

Concept Questions :-

Different types of AC Circuits
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

An alternating current of frequency ‘f’ is flowing in a circuit containing a resistance R and a choke L in series. The impedance of this circuit is

(1) R + 2πfL

(2) $\sqrt{{R}^{2}+4{\pi }^{2}{f}^{2}{L}^{2}}$

(3) $\sqrt{{R}^{2}+{L}^{2}}$

(4) $\sqrt{{R}^{2}+2\pi fL}$

Concept Questions :-

Different types of AC Circuits
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A resistance of 300 Ω and an inductance of $\frac{1}{\pi }$ henry are connected in series to a ac voltage of 20 volts and 200 Hz frequency. The phase angle between the voltage and current is :

(1) ${\mathrm{tan}}^{-1}\frac{4}{3}$

(2) ${\mathrm{tan}}^{-1}\frac{3}{4}$

(3) ${\mathrm{tan}}^{-1}\frac{3}{2}$

(4) ${\mathrm{tan}}^{-1}\frac{2}{5}$

Concept Questions :-

Different types of AC Circuits
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

In a region of uniform magnetic induction B = 10–2 tesla, a circular coil of radius 30 cm and resistance π2 ohm is rotated about an axis that is perpendicular to the direction of B and which forms a diameter of the coil. If the coil rotates at 200 rpm the amplitude of the alternating current induced in the coil is :

(1) 4π2 mA

(2) 30 mA

(3) 6 mA

(4) 200 mA

Concept Questions :-

Different types of AC Circuits
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

In a LCR circuit having L = 8.0 henry, C = 0.5 μF and R = 100 ohm in series. The resonance frequency in radian per second is

(2) 600 Hz

(4) 500 Hz

Concept Questions :-

Different types of AC Circuits
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The impedance of a circuit consists of 3 ohm resistance and 4 ohm reactance. The power factor of the circuit is :

(1) 0.4

(2) 0.6

(3) 0.8

(4) 1.0

Concept Questions :-

Different types of AC Circuits
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The power factor of a good choke coil is:

(1) Nearly zero

(2) Exactly zero

(3) Nearly one

(4) Exactly one

Concept Questions :-

Different types of AC Circuits
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

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

(1) LC

(2) (LC)–1/2

(3) ${\left(\frac{L}{C}\right)}^{-1/2}$

(4) $\frac{C}{L}$

Concept Questions :-

LC oscillations
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

In an ac circuit, a resistance of R ohm is connected in series with an inductance L. If phase angle between voltage and current be 45°, the value of inductive reactance will be

(1) $\frac{R}{4}$

(2) $\frac{R}{2}$

(3) R

(4) Cannot be found with the given data

Concept Questions :-

Different types of AC Circuits