This is a challenging question, but one that helps to make sure you really understand certain concepts. I’ll give you some hints and help, but obviously have to be careful about giving too much away here. It’s good for students to struggle with this question!
First of all, I want to reassure you that you can give a numerical answer for all 4 parts of the question even though there are no resistances given.
Probably the most important first step is to be able to see how the circuits are laid out. Look at each load, one at a time, and think if it is in parallel with other loads or in series. That’s an important distinction because the two different types of circuits behave differently in terms of voltage supply and current. Also, pay attention to the fact that the detector switch is closed.
Once you have determined the type of circuits you are dealing with, you can use what you should know about voltage supply and voltage drop in circuits to figure out the answers.
The videos that you might want to review to help you would be the ones at the end of unit 4, and the ones in unit 5.
Hope that helps – let me know!