The self-inductance of a choke coil is $10\, mH$. When it is connected to a $10\, V$ $dc$ source,the power loss is $20\, W$. When it is connected to a $10\, V$ $ac$ source,the power loss is $10\, W$. The frequency of the $ac$ source is......$Hz$.

  • A
    $50$
  • B
    $60$
  • C
    $80$
  • D
    $100$

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Similar Questions

Match the List-$I$ with List-$II$.
List-$I$ List-$II$
$A$. $AC$ generator $I$. Presence of both $L$ and $C$
$B$. Transformer $II$. Electromagnetic Induction
$C$. Resonance phenomenon to occur $III$. Quality factor
$D$. Sharpness of resonance $IV$. Mutual Inductance

Choose the correct answer from the options given below:

$A$ circuit with an electrical load having impedance $Z$ is connected with an $AC$ source as shown in the diagram. The source voltage varies in time as $V(t) = 300 \sin (400 t) \text{ V}$,where $t$ is time in seconds. List-$I$ shows various options for the load. The possible currents $i(t)$ in the circuit as a function of time are given in List-$II$. Choose the option that describes the correct match between the entries in List-$I$ to those in List-$II$.
List-$I$ List-$II$
$(P)$ Resistor $R = 30 \ \Omega$ $(1)$ $i(t) = 5 \sin(400t)$
$(Q)$ Resistor $R = 30 \ \Omega$ and Inductor $L = 100 \text{ mH}$ $(2)$ $i(t) = 6 \sin(400t + 53^{\circ})$
$(R)$ Capacitor $C = 50 \ \mu\text{F}$,Resistor $R = 30 \ \Omega$,and Inductor $L = 25 \text{ mH}$ $(3)$ $i(t) = 10 \sin(400t)$
$(S)$ Capacitor $C = 50 \ \mu\text{F}$,Resistor $R = 60 \ \Omega$,and Inductor $L = 125 \text{ mH}$ $(4)$ $i(t) = 20 \sin(400t - 90^{\circ})$
$(5)$ $i(t) = 6 \sin(400t - 53^{\circ})$

Mark the incorrect statement.

Assertion: Ohm's law cannot be applied to $a.c.$ circuits.
Reason: Resistance offered by a capacitor for an $a.c.$ source depends upon the frequency of the source.

An electrical device draws $2 \, kW$ power from $AC$ mains $(V_{rms} = 223 \, V = \sqrt{50000} \, V)$. The current lags in phase by $\tan \phi = -\frac{3}{4}$ compared to the voltage. Find $(i)$ $R$,$(ii)$ $X_C - X_L$,and $(iii)$ $I_M$. Another device has twice the values for $R$,$X_C$,and $X_L$. How are the answers affected?

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