Embibe Experts Solutions for Chapter: Alternating Current, Exercise 1: Goa Board-2018

To reduce current in an ac circuit, an inductor coil is preferred to a resistor. Why?

For a purely inductive ac circuit, show that the current lags the voltage by a phase angle of $\frac{\mathrm{\pi }}{2}$ radians. Hence, show that the power dissipated across the inductor is zero. Draw the phasor diagram.

LCR series circuit is connected to an ac source of voltage $V=V_{\circ } \sin \omega t$. Using phasor diagrams, obtain an expression for the impedance and the phase angle between the voltage and the current.

 In an Indian laboratory, a circuit running on low AC voltage is connected to the AC mains through an electrical device .Name the electrical device

 In an Indian laboratory, a circuit running on low AC voltage is connected to the AC mains through an electrical device .If the electrical device is 100% efficient, state whether its input current will be greater or less than the output current.

Show that the voltage and current are always in phase when a resistance is connected across an A.C. source. Draw the phasor diagram for it. To tune a radio over a frequency range of $800 kHz to 1200 kHz$ , inductance ‘L’ is kept constant  and the corresponding capacitance is varied from $C_1 to C_2$ . Compare $C_1 to C_2$.

What is the phase difference between the input and the output voltage in a transistor oscillator circuit?