Show that the average power transferred to an a.c. circuit is in general given by `P= V_(r.m.s) I _(r.m.s) R//Z`. Where R is the resistance in the circuit.

Draw a simple circuit of a CE transistor amplifier. Explain its working. Show that the voltage gain, A_V of the amplifier is given by A_v = - ( beta_(ac) R_L )/(r_i) where beta_(Ac) is the current gain, R_L is the load resistance and r_1 is the input resistance of the transistor. What is the significance of the negative sign in the expression for the voltage gain?

Instantaneous voltage from an a.c. source is given by E=300 sin 314 t. What is the r.m.s. voltage of the source?

A cell of emf E and internal resistance r is connected to two external resistance R_(1) " and " R_(2) and a perfect ammeter. The current in the circuit is measured in four different situations : (i) without any external resistance in the circuit

Derive the expression for the impedance of an a.c. circuit with an inductor L and a resistor R in series.

A cell of emf E and internal resistance r is connected to external resistance R_1 and R_2 and a perfect ammeter. The current in the circuit is measured in four different situations. without any external resistance in the circuit with resistance R _1 only with R_1 and R_2 in parallel combination with R_1 and R_2 in series combination the currents measured in the four cases are 0.42 A, 1.05A, 1.4A adn 4.2 A, but not necessarily in that order. Identify the currents corresponding to the four case mentioned above.