List of top Physics Questions on Alternating current asked in MHT CET

An alternating voltage is given by \(V=V_{0}\sin \left(\omega t+\frac{\pi }{4}\right)\). The time when the voltage is maximum for the first time is
(\(T\) = periodic time of the alternating voltage, \(\cos 0^{\circ }=\sin 90^{\circ }=1\))

An AC source is \(120\) V - \(60\) Hz. The value of voltage after \(\frac{1}{720}\) s from start will be \(\left(\sin 30^{\circ }=\frac{1}{2}\right)\)

An alternating voltage is \(E=100\,\sin \left(\omega t+\frac{\pi }{6}\right)\) V. The voltage will be maximum for the first time when t is
\(\left(\sin \frac{\pi }{2}=1\right)\) (T = Periodic time)

A resistance of \(20\Omega\) is connected to a source of alternating potential \(V=220\,\sin (100\pi t)\). The time taken by current to change from its peak value to r.m.s. value is \(\left(\sin \frac{\pi }{4}=\frac{1}{\sqrt{2}}\right)\)

In an AC circuit, the current is \(I=100\,\sin (5t)\) A. The value of \(I_{rms}\) is

In an ideal LC circuit, if the energy stored in the inductor is equal to energy stored in a capacitor, then the magnitude of charge Q stored in capacitor is ( \(Q_{0}\) is the maximum charge)

An alternating current is given by \(i=i_{1}\sin \omega t-i_{2}\cos \omega t\). The rms current is given by

The alternating voltage is given by \(V=V_{0}\sin \left(\omega t+\frac{\pi }{6}\right)\). When will the voltage be maximum for the first time?
\(\{\sin (90)^{\circ }=1\}\)

If a coil of inductance L and resistance R is connected to AC source with voltage V and angular frequency \(\omega\) and current I, then the inductance L is

If the r.m.s. current in an a.c. circuit is \(5\) A, having frequency \(50\) Hz. The value of current \(\frac{1}{300}\) s after its value becomes zero (in A) is
\(\{\sin (\pi /3)=(3)^{0.5}/2\}\)

The r.m.s value of current in a 50 Hz A.C. circuit is 10 A. The average value of A.C. current over a cycle is

Given below are the two circuits, choose the correct option.

When an inductance '\(L\)' and resistor '\(R\)' are connected in series to \(25\)V, \(50\) Hz supply, a current of \(0.5\) A flows in the circuit. The current lags behind in phase from applied voltage by \((\frac{π}{3})\) radian. The value of R is \((cos60^{\circ} = \frac{1}{2})\)

In an oscillating LC circuit the maximum charge on the capacitor is Q. When the energy is stored equally between the electric and magnetic fields, the charge on the capacitor (q) is

An alternating voltage \(e = 150\sqrt{2}sin100t\) volt is applied to a capacitor of capacity \(2 μ\text{F}\). The root mean square value of current in the circuit is

An a.c. source is applied to a series LR circuit with \(X_L = 3R\) and power factor is \(X_1\). Now a capacitor with \(X_c = R\) is added in series to LR circuit and power factor is \(X_2\). The ratio \(X_1\) to \(X_2\) is

In an a.c. circuit, a resistance R is connected in series with an inductance 'L'. If phase angle between voltage and current is \(45^{\circ}\), the value of inductive reactance will be
(\(sin45^{\circ} = \frac{1}{\sqrt{2}} = cos45^{\circ}\))

In an oscillating LC circuit, the maximum charge on the capacitor is Q. When the energy is stored equally between the electric and magnetic fields, the charge on the capacitor becomes

Alternating current of peak value \((\frac{2}{π})\) A flows through the primary coil of a transformer. The coefficient of mutual inductance between primary and secondary coils is 1H. The peak value of induced e.m.f. in the secondary coil is
(Frequency of a.c. = 50 Hz)

An alternating e.m.f. is given by \(e = e_0sinωt\). In what time the e.m.f. will have half its maximum value, if 'e' Starts from zero?

An electric lamp connected in series with a capacitor and an a.c source is glowing with certain brightness. On reducing the frequency of source the brightness of the lamp

An alternating e.m.f. is given by \(e = e_0sinωt\). In what time the e.m.f. will have half its maximum value, if 'e' starts from zero? (\(sin30^{\circ} = 0.5\))

A light bulb connected in series with a capacitor and an a.c.source is glowing with certain brightness. On reducing the value of capacitance and frequency respectively, the brightness of the bulb

In an AC circuit \(E = 50sin(500t)\), \(I = 600sin(500t+\frac{π}{3})mA\). What is the power dissipated in the circuit? [\(cos60^{\circ} = 0.5\)]

If '\(\lambda_1\)' and '\(\lambda_2\)' are the wavelengths of the first member of the Balmer and Paschen series, in hydrogen atom respectively, then the ratio of respective frequencies, \(f_1/f_2\) , is