A resistor and capacitor are connected in series across an ac generator. The emf of the generator is given byv(t) = V0 cos ωt, where V0 = 120 V,ω = 120π rad/s, R = 400 Ω , and C = 4.0μF . (a) What is the impedance of the circuit?
(b) What is the amplitude of the current through the resistor?
(c) Write an expression for the current through the resistor.
(d) Write expressions representing the voltages across the resistor and across the capacitor.

The temperature in gavin's oven is a sinusoidal function of time. gavin sets his oven so that it has a maximum temperature of 280°f and a minimum temperature of 240°. once the temperature hits 280°, it takes 20 minutes before it is 280° again. gavin's cake needs to be in the oven for 30 minutes at temperatures at or above 270°. he puts the cake into the oven when it is at 260° and rising. how long will gavin need to leave the cake in the oven? (round your answer to the nearest minute.)