heating element

an electric heating element is connected to a 110 v circuit and a current of 3.2 A is flowing through the element. How much energy is used up during a period of 5 hours by the element? (A) 352 wh (b) 550wh (c) 1,760wh (d) 2,580wh ?

Ohms

A complete circuit contains two parallel-connected devices and a generator for providing the electromotive force. the resistance of the first device is 12ohms, the resistance of the second device is 4 ohms, and the voltage developed by the generator is 40v. what is the magnitude of the current flowing through the first device? (a) 3.33a (b) 8a (c)10aor (d) 13.32a ?

I came across this problem while trying to understand more about circuit theory

1- Assume a passive network N composed of resistors, inductors, and capacitors A- How can you modify N such that each and every natural frequency is shifted one unit to left? (i.e. its real part is reduced by 1) B- How can you modify N such that each and every natural frequency is shifted one unit to right? (i.e. its real part is increased by 1)

Circuit theory related problem

Assume an infinite network made of 1nH inductors as shown below. Furthermore assume that there is not mutual inductance. What is the effective inductance between points A and B? [The number only, i.e. Leff =?] (see diagram in the attached file)

Source and load question for train hobby project

Have four circuits. One takes 9Vdc, two 5Vdc, and last one takes 12Vdc. Have variable transformer for source. How do I calculate or choose the voltage needed to run all four circuits with out blowing them all up, and at the same time run each circuit by themselves or two at a time or three, etc. How do I know how much current the source needs and where do I place leads to measure current and voltage for each individual circuit?