Answer:
One battery, two resistors, two switches, three light bulbs
Explanation:
Each component is indicated with the following symbols:
- Battery: it is the one on the right, consisting of two longer lines and two shorter lines. It is the device that provides the electromotive force to the circuit
- Resistors: they are the devices on the bottom line, consisting of zig-zag lines. Resistors are pieces of circuit that resist to the flow of current in the circuit.
- Switches: they are labelled with a line with two dots at both ends. They can be opened/closed in order to stop/allow the flow of current in the circuit.
- Light bulbs: they are labelled with a circle filled with a X.
Answer:
RL=100K → Vo=9.90 mV
RL=10K → Vo=9.09 mV
RL=1K → Vo=5 mV
RL=100 → Vo=909.09 μV
In order to obtain 80% of the power source we have to put a resistor of 4 KOhm.
Explanation:
Here we have a power source in serie with a resistor of 1K and RL, in order to obtain the Vo voltage we have to apply the voltage divider rule, that states:

Substituing the resistor values of RL we obtained the following results:
RL=100K → Vo=9.90 mV
RL=10K → Vo=9.09 mV
RL=1K → Vo=5 mV
RL=100 → Vo=909.09 μV
In order to find the lowest value that gives us 80% of the source voltage we have to use the voltage divider rule again and make the Vo equal to 0.8 Vin:

The result of the last equation is 4000, so in order to obtain 80% of the power source we have to put a resistor of 4 KOhm.
It's negative electric charge
The average velocity as velocity is equal to displacement/time
As you crank the variable resistor to higher resistance, the total current in the loop decreases. The power dissipated by the light bulb ... the heat and brightness it produces ... depend directly on the current through it, so they decrease too. Your circuit is a perfect incandescent light dimmer circuit.