$\mathrm{If}<mspace\; width="1em"></mspace>{\mathrm{X}}_{\mathrm{L}}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>{\mathrm{X}}_{\mathrm{C}}<mspace\; width="1em"></mspace>\mathrm{then}<mspace\; width="1em"></mspace>\mathrm{the}<mspace\; width="1em"></mspace>\mathrm{reading}<mspace\; width="1em"></mspace>\mathrm{of}<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>\mathrm{ideal}<mspace\; width="1em"></mspace>\mathrm{voltmeter}<mspace\; width="1em"></mspace>\mathrm{is}:<mspace\; width="1em"></mspace>$

1.  $\mathrm{V}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>{\mathrm{V}}_{\mathrm{L}}<mspace\; width="1em"></mspace>-<mspace\; width="1em"></mspace>{\mathrm{V}}_{\mathrm{C}}<mspace\; width="1em"></mspace>$

2.  $\mathrm{V}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>\sqrt{{\mathrm{V}}_{\mathrm{R}}^2<mspace\; width="1em"></mspace>+<mspace\; width="1em"></mspace>{\mathrm{V}}_{\mathrm{L}}^2}<mspace\; width="1em"></mspace>$

3.  $\mathrm{V}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>\sqrt{{\mathrm{V}}_{\mathrm{R}}^2<mspace\; width="1em"></mspace>+<mspace\; width="1em"></mspace>{\left({\mathrm{V}}_{\mathrm{L}}<mspace\; width="1em"></mspace>-<mspace\; width="1em"></mspace>{\mathrm{V}}_{\mathrm{C}}\right)}^2}$

4.  Zero

The phase difference between the current and voltage of LCR circuit in series combination at resonance is 

1. 0

2. π/2

3. π

4. –π

In a series resonant circuit, the ac voltage across resistance R, inductance L and capacitance C are 5 V, 10 V and 10 V respectively. The ac voltage applied to the circuit will be 

1. 20 V

2. 10 V

3. 5 V

4. 25 V

A transistor-oscillator using a resonant circuit with an inductance \(L\) (of negligible resistance) and a capacitance \(C\) has a frequency \(f.\) If \(L\) is doubled and \(C\) is changed to \(4C,\) the frequency will be:
1. \(f/4\)
2. \(8f\)
3. \(f/2\sqrt2\)
4. \(f/2\)

In the LCR-circuit shown below, if the reading of the voltmeters $V_{1<mspace\; width="1em"></mspace>}$and $V_2$ are same, then

1. ${\omega }^2=\frac{1}{LC}$

2. Reading of the voltmeter V is 50 V

3. Reading of the ammeter A is 5 A

4. All of these