Question 1 : <span>In an A.C source, peak value of A.C is the maximum value of current in either direction of the cycle. Root mean square (RMS) is also defined as the direct current which produces the same heating effect in a resistor as the actual A.C.</span><div>A.C measuring instrument measures its</div>
Question 2 :
A parallel plate condenser of capacity $100\ pF$ is connected to $230\ V$ of $AC$ supply of $300\ rad/sec$ frequency. The $rms$ value of displacement current
Question 3 :
If the instantaneous current in a circuit is given by $\displaystyle I = 2 cos (\omega t + \varphi)$ amperes, the rms value of current is
Question 5 :
A.C power is transmitted from a power house at a high voltage as
Question 6 :
What is the r.m.s. value of the current for A.C. current $I=100\cos(200t+45^o)A$.
Question 7 :
The instantaneous value of emf and current in an A.C. circuit are; $E=1.414sin\left ( 100\pi t-\frac{\pi }{4} \right )$ , $I=0.707sin(100\pi t)$ . The admittance of the circuit will be _______ mho.<br/>
Question 9 : <p class="wysiwyg-text-align-justify"><span class="wysiwyg-font-size-medium"><span class="wysiwyg-font-size-small">The root mean square value of alternating current (sine function) is equal to</span></span><br></p>
Question 11 :
State whether given statement is True or False<br/>An alternating current cannot be used for electroplating.
Question 12 :
An inductive coil has a resistance of 100 $\Omega $ . When an AC signal of frequency 1000 Hz is applied to the coil, the voltage leads the current by $45^{o}$. The inductance of the coil is<br>
Question 14 :
An AC source of voltage $E = 20 \sin 100 t$ is connected across a resistance $20 \Omega$. The rms value of current in the circuit is
Question 15 :
If instantaneous current is given by $i= 4 cos (\omega t + \phi )$ amperes, then the r.m.s. value of current is
Question 16 :
The heat produced in a given resistance in a given time by the sinusoidal current ${ I }_{ 0 }\sin { \omega t} $ will be the same as that of a steady current of magnitude nearly
Question 17 :
The instantaneous value of emf and current in an A.C. circuit are; $E=1.414sin\left ( 100\pi t-\frac{\pi }{4} \right )$ , $I=0.707sin(100\pi t)$ . The impedance of the circuit will be<br/>
Question 19 :
The inductive reactance of a choke coil of $\displaystyle 1/4 \pi\ mH$ in an $AC$ circuit of $50\ Hz,$ will be
Question 20 :
At what voltage is the electric power from generating station transmitted ?
Question 21 :
An AC source has a rms value of voltage of $\dfrac{200}{\sqrt{2}}$. The value of voltage after $\dfrac{1}{600}$ s from the start when frequency is 50 Hz is
Question 22 :
At what time (from zero) will the alternating voltage become $\dfrac {1}{\sqrt {2}}$ times of its peak value where $T$ is the periodic time?
Question 23 :
An electric current has both DC and AC components. DC component of $8 A$ and AC component is given as $I=6\sin { \omega t } A$. So, ${ I }_{ rms }$ value of resultant current is ___________.
Question 24 :
An inductor-coil having some resistance is connected to an $AC$ source. Which of the following quantities have zero average value over a cycle?
Question 25 :
An inductor of 1 H is connected across a 220 V, 50 Hz supply. The peak value of the current is approximately<span><br></span>
Question 26 :
If $ i = t^2 \, 0 < t < T $ then r.m.s. value of current is
Question 27 :
If $E=100\sin { \left( 100t \right) }$ volt and $I=100\sin { \left( 100t+\dfrac { \pi }{ 3 } \right) } mA$ are the instantaneous voltage and current, then the rms values of voltage and current are respectively
Question 28 :
The peak value of an alternating current is $5$A and its frequency is $60$Hz. Find its rms value and time taken to reach the peak value of current starting from zero.
Question 29 :
If the A.C. main supply is of 220 V then the average e.m.f. during positive half cycle will be:<br/>
Question 30 :
High voltage transmission results in lower current and hence lower heat loss. AC is preferred over DC because
Question 31 :
The Joules heating effect for an electric heater in A.C and in D.C. circuit is
Question 32 :
The rms value of current in an ac circuit is 25 A, then peak current is
Question 33 :
The frequency of an alternating voltage is 50 cycle/sec and its amplitude is 120V. Then the rms value of voltage is
Question 34 :
If the r.m.s. value of A.C. is $l_{rms}$ then peak value is -
Question 35 :
r.m.s. value of current $i=3+4\sin { (\omega t } +\dfrac { \pi }{ 3 }$) is:
Question 36 :
Assertion: In the pure resistive element of a series LCR ac circuit , the maximum value of rms current increases with increase in the angular frequency of the applied emf .
Reason: $ I_{max} = \dfrac{\varepsilon_{max}}{Z} , Z = \sqrt{R^2 + \left (\omega L - \dfrac{1}{\omega C } \right )^{2}} $ , where $ I_{max} $ is the peak current in a cycle .
Question 37 :
An alternating current is given by the equation $i = i_1 cos \omega t + i_2 sin \omega t$. The r.m.s. current is given by:
Question 38 :
When a series combination of $L$ and $R$ are connected with a $10V$, $50HZ$ A.C. source, a current 1A flows in the circuit. The voltage leads the current by a phase angle of $\pi/3$ radian. Then the resistance is<br>
Question 39 :
An alternating current is given by $I=I_1\cos\omega t+I_2\sin\omega t$. The RMS value of current is given by?
Question 40 :
A generator with a circular coil of $100$ turns of area $2\times { 10 }^{ -2 }{ m }^{ 2 }$ is immersed in a $0.01T$ magnetic field and rotated at a frequency of $50Hz$. The maximum emf which is produced during a cycle is
Question 41 :
An AC source of angular frequency $\omega $ is fed across a resistor R and a capacitor C in series. The current registered is I. If now the frequency of source is changed to $\omega /3$ (but maintaining the same voltage), the current in the circuit is found to be halved. The ratio of reactance to resistance at the original frequency $\omega $ is<br/>
Question 42 :
An AC current is given by $I=I_0+I_1\sin\omega t$ then the rms value will be.
Question 44 :
If a direct current of value $a$ ampere is superimposed on an alternative current $I = b\sin\omega t$ ampere flowing through a wire, what is the effective value of the resulting current in the circuit?
Question 45 :
A pure resistive circuit element $x$ when connected to an A.C. supply of peak voltage 100 V gives a peak current of 4 A which is in phase with the voltage. A second circuit element y when connected to the same AC supply also gives the same value of peak current but the current lags behind by $90^{0}$. If the series combination of $x$ and $y$ is connected to the same supply, rms value of current is_________<br/>
Question 46 :
An alternating current is given by $i=i_{1} cos \omega t+i_{2} sin \omega t.$ The rms current is given by:<br/>
Question 47 :
If an AC main supply is given to be 220 V. The average emf during a positive half cycle will be
Question 48 :
A generator produces a time varying voltage given by $V=240\sin 120t$, where $t$ is in second. The rms voltage and frequency are
