Question 1 :
In a step-up transformer, the number of turns in the primary are .................. than the number turns in the secondary.

Question 2 :
The ratio between the primary voltage and the secondary voltage in a transformer is equal to:<br/>

Question 3 :
An alternating voltage frequency $\omega$ is induced in electric circuit consisting of an inductance $L$ and capacitance $C$, connected in parallel. Then across the inductance coil the<br>(i) current is maximum when ${\omega}^{2}=1/(LC)$<br>(ii) current is minimum when&nbsp;${\omega}^{2}=1/(LC)$<br>(iii) voltage is minimum when&nbsp;${\omega}^{2}=1/(LC)$<br>(iv) voltage is maximum when&nbsp;${\omega}^{2}=1/(LC)$

Question 5 :
<p>Primary winding and secondary winding of a transformer has<br>100 and 300 turns respectively. If its input power is 60 W then output power of<br>the transformer will be</p>

Question 6 :
A transformer steps up an $AC$&nbsp;supply from&nbsp;$220 V$&nbsp;to&nbsp;$2200&nbsp;V$. If the secondary coil of the transformer has&nbsp;$2000$&nbsp;turns, the number of turns in its primary coil will be:&nbsp;

Question 7 :
The correct formula for the angular frequency $\omega_0$ of an $L-C$ resonant circuit is

Question 8 :
In a $LC$ circuit. Angular frequency at resonance is $w$. What will be the new angular frequency when inductor's introduces is made $2$ times and capacitance is made $4$ times?

Question 9 :
What do we name the device which increases the emf ?<br/>

Question 10 :
Assertion (A): More the turns more is the<br>resistance<br>Reason(R): Impedance of primary and secondary<br>in a transformer is directly proportional to number<br>of turns in the coils.<br><br>

Question 11 :
When&nbsp;the values of inductance and capacitance in an $L-C$ circuit are $0.5\ &nbsp;H$ and $8\ \mu$F respectively then current&nbsp;in&nbsp;the circuit is maximum. The angular frequency of&nbsp;alternating&nbsp;e.m.f. applied in the circuit will be

Question 12 :
In an ac circuit with voltage V and current I, the power dissipated is

Question 13 :
The power loss in an $AC$ circuit is $E_{rms}$ $I_{rms}$, when in the circuit there is only

Question 14 :
In a circuit $LC = 10^{-3}H, C = 10^{-3} F$. Find angular frequency.<br/>

Question 15 :
The current which does not contribute to the power consumed in an AC circuit is called:

Question 16 :
In a transformer number of turns in primary circuit is $500$ and in secondary circuit number of turns is $10$ and load resistance is $10\Omega$ and voltage of secondary coil is $50$V then find the current in primary circuit.

Question 17 :
A power transmission line feeds input power at $2300\ V$ to a step-down transformer, with its primary winding having $4000$ turns. What should be the number of turns in the secondary winding in order to get output power at $230\ V$?

Question 18 :
An inductor of inductance 2.0 mH is connect across a charge capacitor of capacittance 5.0 uF , and the resulting LC circuit is set oscillating at natural frequency. Let Q denote the instantaneous charge on the capacitor, and I the current in the circuit. It is found the maximum value of Q is 200 uC .When Q=100uC the value of $\dfrac{dI}{dt} $ is found to be $10^{x}$ A/s. Find the value of x is then<br/>

Question 19 :
In the secondary coil of a step up transformer, the number of turns of the copper wire are :

Question 20 :
A source of 220V is applied in an A.C. circuit. The value of resistance is $220 \Omega$. Frequency &amp; inductance are 50 Hz and 0.7 H, then wattless current is&nbsp;

Question 21 :
A condenser of $250\mu F$ is connected in parallel to a cell of inductance $0.16$ mH, while its effective resistance is while its. Determine the resonant frequency.

Question 22 :
An LC circuit contains a 20 mH inductor&nbsp;and a 50 .$\mu$ F capacitor with an initial charge of 10 mC. The resistance&nbsp;of the circuit is.negligible. Let the instant at which the circuit which is&nbsp;closed be t = 0. At what time the energy stored is completely magnetic?

Question 23 :
The number of turns in the primary coil of a transformer is 200 and the number turns in the secondary coil is 10 If 240 volt a.c is applied&nbsp; to the primary the output from seconsry will be:

Question 24 :
Write the following steps in a sequential order to find the current and voltage in the secondary coil. The ratio of the number of turns of a primary to a secondary coil, current through the primary coil and input power are given.<br/>(a) Let the given data be taken as $\displaystyle \dfrac{N_1}{N_2}$ (turn-ratio), $i_1$, (input current) and $P$ (input power).<div><br/>(b) Substitute the given values of $\displaystyle \dfrac{N_1}{N_2}$ and $i_1$, in the above formula and get the value of $i_2$.</div><div><br/>(c) Write the relation between turn-ratio and the currents as $\displaystyle \dfrac{N_1}{N_2} = \dfrac{i_2}{i_1}$, where $i_2$ is the current in the secondary coil.</div><div><br/>(d) Write the relation between input power and output power in terms of $V_1, i_1, V_2, i_2$ i.e. $V_1i_1=V_2i_2=P$, where $V_1$ and $V_2$ are the voltage in the primary and secondary coils respectively.</div><div><br/>(e) Substitute the values of $i_2$ and P in the above relation to get the value of $V_2$.<br/></div>

Question 25 :
How many primary volts must be applied to a transformer with a secondary to primary turns ratio of $0.1$ to obtain a secondary voltage of $9 V$?<br/>

Question 26 :
The ratio of no. of coils in the secondary to primary step up transformer is $4:1$. If a current of $4\ $ <br> $A$ is applied to the primary, the current in secondary will be:

Question 27 :
A transformer converts 230 V A.C into 1035 V A.C. If the number of turns in the primary is 200, the number of turns in the secondary is :<br/>

Question 28 :
In a transformer, the number of turns in the primary and secondary coils are 2000 and 4000 respectively. If the primary coil is connected across 120 V AC, the potential difference across each turn of the secondary coil will be :<br/>

Question 30 :
A power transmission line feeds input power at 2400 V to a step down transformer with its primary winding having 4000 turns. What should be the number of turns in the secondary winding in order to get output power at 240 V ?

Question 31 :
A coil of inductance $L$ has an inductive reactance of $ X_L $&nbsp; in an AC circuit in which the effective current is $I$. The coil is made from a super-conducting material and has no resistance. The rate at which&nbsp;power is dissipated in the coil is

Question 32 :
An L-C circuit consists of an inductor with $L = 0.09\ H$ and a capacitor of $C = 4 \times 10^{-4} F$. The initial charge on the capacitor is $5.00\ \mu C$, and the initial current in the inductor is zero. <div>What is the maximum current in the inductor?</div>

Question 33 :
A step up transformer has a turn ratio of 10: 1. A cell of e.m.f. 2 volts is fed to the primary. A secondary voltage developed is :

Question 34 :
<span>In an oscillating $L-C$ circuit in which $C=4.00\mu F$, the maximum potential across the capacitor during the oscillations is $1.50V$ and the maximum current through the inductor is $50.0mA$. </span>How much time does the charge on the capacitor take to rise from zero to its maximum value?

Question 35 :
An inductor $200 mH,$ capacitor $500 \mu F$ and resistor $10 \Omega$ are connected in series with a $100 V$ variable frequency ac source. What is the frequency at which the power factor of the circuit is unity?

Question 36 :
If a transformer have turn ratio $5$ , frequency $50 Hz$ root mean square value of potential difference on primary $100$ volts and the resistance of the secondary winding is $500 \Omega $ then the peak value of voltage in secondary winding will be (the efficiency of the transformer is hundred percent)&nbsp;

Question 37 :
<span>An $L-C$ circuit consists of an inductor of $L=0.0900H$ and a capacitor of $C=4\times {10}^{-4}F$. The initial charge on the capacitor is $5.00\mu C$ and the initial current in the inductor is zero</span>. When the current in the inductor has half its maximum value, what is the energy stored in the inductor?

Question 38 :
A LC circuit is in the state of resonance. If C=0.1 $/mu F$ and L = 0.25 henry. Neglecting ohmic resistance of circuit what is the frequency of oscillations