The current through a fixed resistor of resistance 10Ω varies with time according to I(t)=0.50+0.003t amperes, where t is the time in seconds (0≤t≤50). Using this information, answer the following:
(i) Write an expression for the instantaneous electrical power in the resistor as a function of time.
(ii) Calculate the power at t=20s and at t=50s, giving your answers up to two decimal places.
(iii) Find the ratio of the power at t=50s to that at t=20s.