NCERT Solutions for Chapter: Alternating Current, Exercise 3: SA

A device $‘X’$ is connected to an a.c source. The variation of voltage, current, and power in one complete cycle is shown in Fig 7.5.

(a) Which curve shows power consumption over a full cycle? 

A device $‘X’$ is connected to an a.c source. The variation of voltage, current and power in one complete cycle is shown in Fig 7.5.

(b) What is the average power consumption over a cycle? 

A device $‘X’$ is connected to an a.c source. The variation of voltage, current and power in one complete cycle is shown in Fig 7.5.

 (c) Identify the device $‘X’$.

Both alternating current and direct current are measured in amperes. But how is the ampere defined for an alternating current?

A coil of $0.01$ henry inductance and $1$ ohm resistance is connected to $200$ volt, $50 Hz$ ac supply. Find the impedance of the circuit and time lag between max. alternating voltage and current.

A $60 W$ load is connected to the secondary of a transformer whose primary draws line voltage. If a current of $0.54 A$ flows in the load, what is the current in the primary coil? Comment on the type of transformer being used.

Explain why the reactance provided by a capacitor to an alternating current decreases with increasing frequency.

Explain why the reactance offered by an inductor increases with the increasing frequency of an alternating voltage.