In a LCR series circuit, the potential difference between the terminals of the inductance is 60 V between the terminals of the capacitor is 30 V and that across the resistance is 40 V. Then, supply voltage will be equal to

• 50 V

• 70 V

• 130 V

• 10 V

A choke is preferred to a resistance for limiting current in AC circuit because

• choke is cheap

• there is no wastage of power

• choke is compact in size

• choke is a good absorber of heat

An electric bulb has a rated power of 50 W at 100 V. If it is used on an AC source 200 V, 50 Hz, a choke has to be used in series with it. This choke should have an inductance of

• 0.1 mH

• 1 mH

• 0.1 H

• 1.1 H

An inductance of $\left(\frac{200}{\mathrm{\pi }}\right) \mathrm{mH}$, a capacitance of $\left(\frac{{10}^{-3}}{\mathrm{\pi }}\right) \mathrm{F}$ and a resistance of 10 Ω are connected in series with an AC source 220 V, 50 Hz. The phase angle of the circuit is

• $\frac{\mathrm{\pi }}{6}$

• $\frac{\mathrm{\pi }}{4}$

• $\frac{\mathrm{\pi }}{2}$

• $\frac{\mathrm{\pi }}{3}$

A step-down transformer reduces the voltage of a transmission line from 2200 V to 220 V. The power delivered by it is 880 W and its efficiency is 88%. The input current is

• 4.65 mA

• 0.045 A

• 0.45 A

• 4.65 A

The value of alternating emf E in the given circuit will be

• 220 V

• 140 V

• 100 V

• 20 V

A current of 5 A is flowing at 220 V in the primary coil of a transformer. If the voltage produced in the secondary coil is 2200 V and 50% of power is lost, then the current in secondary will be

• 2.5 A

• 5 A

• 0.25 A

• 0.5 A

For a series LCR circuit at resonance, the statement which is not true is

• Peak energy stored by a capacitor = peak energy stored by an inductor.

• Average power = apparent power

• Wattless current is zero.

• Power factor is zero.

An electric heater rated 220 V and 550 W is connected to AC mains. The current drawn by it is

• 0.8 A

• 2.5 A

• 0.4 A

• 1.25 A

A resistor and a capacitor are connected in series with an AC source. If the potential drop across the capacitor is 5 V and that across resistor is 12 V, then applied voltage is

• 13 V

• 17 V

• 5 V

• 12 V