PLEASE HELP IM BEGGING ITS NOT EVEN HARD I JUST DIDNT PAY ATTENTION IN CLASS 30 POINTS An electric heater connected to a power supply is operating at 200 Watts. If the current and the voltage to the heater are both doubled, how many joules per second of electrical energy will be converted to heat?

Asteel tube (k=50 w/mk) of inner and outer diameter di = 20mm and do=26mm, respectively, is used to transfer heat from hot gases flowing over the tube (h-hot = 200w/m2k) to cold water flowing through the tube (h-cold = 8000 w/m2k). what is the cold-side overall heat transfer coefficient uc? to enhance heat transfer 16 straight fins of rectangular profile are installed longitudinally along the outer surface of the tube. the fins are equally spaced around the circumference of the tube, each having a thickness of 2mm and a length of 15mm. what is the corresponding overall heat transfer coefficient uc? *solve for uc in both cases*