A thyristor is connected in series with a load resistor RL and a 60-Hz sinusoidal voltage source with an rms voltage of V. A phase control circuit is used to set the trigger angle a so that a specified amount of power is delivered to the load. The on-state voltage of the thyristor is given by VON = 1.0+ Roni(t) where Ron is the on- state resistance of the thyristor and i(t) is the current flowing in the circuit through RL and the thyristor. Develop an expression for the average power dissipated in the thyristor as a function of the trigger angle a