Wildcard 1
Wildcard 2
Electric Charge
Coulomb Force
Electric Fields
100
Why can’t we see through walls?
We see the photons emitted by electron energy level jumps, not physical objects. Our eyes have a sample rate where they calculate photons for a time, then produce an image.
100
What element is the most common in air?
Nitrogen, it’s about 70%.
100
What are the units of electric charge?
coulombs
100
What are the units of the coulomb force?
N (Newtons)
100
What are the units of electric field strength?
N/C
200
Do you feel your own weight?
No, you feel the force of the world pushing upwards on your feet.
200
Which freezes faster, hot water or cold water?
Sometimes hot water, but that’s not always true.
200
What are the base SI units of electric charge?
A*s (amps times seconds)
200
What is the force felt by two 1C charges separated by 1m?
8.99*10^9N
200
What are the base SI units of electric field strength?
kg*m/(A*s^3)
300
How far are you from Earth right now?
One radius of Earth, 6378km.
300
What is the average depth of the Pacific Ocean?
4280 meters
300
What is the net charge of a Lithium ion with one more electron than proton?
-1.602*10^-19C
300
Where is coulomb force the weakest?
At the halfway point between two charges of the same magnitude and sign.
300
What is the electric field strength 1m away from a charge of magnitude 1nC?
8.99 N/C
400
Where does sound travel faster, in the air or in water?
It’s much faster in water. In air 
, in water 
.
400
Why are sunsets red?
Earth’s atmosphere blocks more blue light than right light, so if the light passes through more atmosphere, it looks redder.
400
What is the word for the process of transferring charge without physical contact?
induction
400
If the distance between two charges increases by 3x, by what factor does the coulomb force change?
9x weaker
400
What magnitude of charge creates an electric field of strength 450,000 N/C at a distance of 1cm?
5nC
500
Are the atoms in your feet touching the atoms in the floor?
No, they’re separated by about 0.5nm due to electric repulsion.
500
Why do bubbles pop?
The internal pressure inside of the bubble is higher than the outside air due to surface tension. If there is a small hole in the thin film, the air escapes.
500
How many elementary charges is 1 coulomb?
6.24*10^18
500
Estimate the repulsion force between two protons in a nucleus. The distance between them is 1 femtometer.
1*10^-15m
231N
500
What distance away from a charge of 1µC does the electric field strength equal 1N/C?
95m