An electric heating element has a resistance of 16 Ω and is connected to a voltage of 120 V. How much current will flow in this  circuit?

Hi could someone please help me with the following question I am given the following information.  The variable resistor Ro in the circuit in (Figure 1) is adjusted for maximum power transfer to Ro. Suppose that v1 = 240 V, and v2 = 140 V a)Find the value of Ro (I found this to be 2.5 Ohms which was correct but I can not do the rest of the parts to this question) b) Find the maximum power that can be delivered to Ro c)What percentage of the total power developed in the circuit is delivered to Ro found in part A? d) (this part is included in the images)  Thanks so much!

A copper wire supplying the heater in Problem 5 will be 6 ft long. What gauge is required if the resistivity must stay below 1.5 ohms/1000 ft to prevent excessive heating of the wire?

A - Explain the symbols, operating principles and usage areas of the diodes given below. (Zener diode: photo diode: led diode: opto coupler) B- Draw the voltage trigger circuit and explain its operation. Explain how there is a difference between the voltage quadrant and the tripler