Electric Field and Potential
Capacitors
Currents and Circuits
Electric Forces
Units and Constants
100
The electric field lines is __________ to the equipotential lines.
perpendicular
100
Capacitance is a ratio between what 2 thing?
the ratio of the change in an electric charge in a system to the corresponding change in its electric potential.(change in charge and change in voltage)
100
Briefly explain how can currents passing though the body determine the percent of body fat?
The resistivity of fat and muscle is different. (Lean muscle is a better conductor than fat)
100
_______ charges attract and _________charges repell
opposite, similiar
100
What is the formula for finding the electric forces?
Newtons of force=kq1q1/r^2
200
the distance between an area of 40V potential to an area of 100V potential is 2nm, what is the electric field between the 2 area if the electric field stayed constant.
change of V over distance, 60V/2E-9, 3E+8
200
Stephen Hawking's family was having a party, everyone seems to be drinking something that looked like water but their facial reaction says otherwise. Stephen wanted to find out what that substance maybe, so he dropped a 500V capacitor inside a cup of the drink and the voltage changed to 20V. What is the dialectic constant of the substance and what substance is it most likely to be?
25, ethanol
200
Briefly explain what the junction law means. And solve the following, at a current cross section, a 4amp current comes in at end A, a 2 amp current comes in at end B, a 3 amp current goes out at end C, how many amp comes in at the end D?
Sum of the current coming in must equal to the sum of the current going out, trick question, 3 amp goes out at end D
200
The initial force was 4N between 2 objects, what is the final force in newtons if 1 objects holds twice as much charge, the other object holds 3 times as much charge and the distance between the 2 doubles
4N(2)(3)/(2^2)
200
what is the ratio between K and epsilon e ?
K = 1/(4pi*e)
300
From an area of -10V to 0V was 2 meters, 0V to 5V was 10meters and 5V to 7V was .01 meters, what is the average electric field from the area of -10V to 7V.
17/(2+10+.01)=?
300
A fully charged 6V battery is connected to a parallel capacitor thats spread 1 cm apart. What is the electric field between the capacitors assuming we are using an ideal capacitor?
the voltage difference between the battery is 6, so 6/.01 equals 600N/C
300
Explain the relationship between potential difference, electric current, and resistance, give units for each variable.
R(ohms)=V(Vz)/I(Amp)
300
Superman and Batman are fighting in a storm where they are infused with negative charges. Superman has 4 times as much charges as batman because of his alien body. How much force is exerted onto batman by superman as compared to the forces exerted from batman to superman?
they are the same
300
What is the formula for finding the electric forces between 2 objects and what are the units for each component, and the value for each constant?
N=kCC/(MM) k=8.99E9 NMM/(CC)
400
A proton started out with no velocity moved from an area of low potential(4V) to an area of higher potential(6V). What is the final velocity if no outside force is acted upon the proton?
KE(i)+PE(i)=KE(f)+PE(f) KE(i)=0 PE(i)=q4 KE(f)=? PE(f)=q6
400
An ideal parallel plate capacitor spread 1 micrometer apart has a radius of 6cm. Assuming there is water in between the capacitors(with a dialetic constant of 80) what is the capacitance?
KeA/d [80(8.85E-12)(3.14)(.06)^2]/(.06) Farad
400
At a certain cross shaped junction with a total of 4 openings, 2 sides has openings that has current flowing in, 1 side has current flowing out. (All above stated currents are constant) What could be the behavior of the current of the last opening.
All the currents must add up to zero, so the last opening could be in or out depending on the strength of the other portions. The current must also be constant.
400
Jack is a very positive person while Jill is a very negative person. What kind of electric forces would they exert on each other and how strong would that force be?
Human beings are almost electrically neutral, so they wouldn't exert any significant electric forces on each other. Their personality does not effect that...
400
What is the formula for finding the electric potential due to a single source charge? And what are the units?
Nm/C=kC/M
500
A electron's initial speed is 40,000m/s and moved from an area of high potential(2V) to an area of lower potential. At what electric potential would the electron stop moving or would the electron escape the potential field? If so, how fast would the electron be moving after it escapes the field
Board
500
A light saber uses parallel capacitors to store its energy. A 6 mF capacitor is charged to 2 million voltz. How much energy is stored in the capacitor? And how much charge is stored in the capacitor?
Potential energy = QV/2 C=Q/V
500
Tesla was testing the potential difference of his battery compared to the brightness of a connected light bulb. So tesla started the battery at 2V and increased its voltage by 2V every minute. Tesla measured the the current increased by 1amp every minute(assuming the wire has no resistance). The light bulb blew up 10 mins after becoming brighter and brighter due to the voltage chance. At what waltage of power going though the light bulb, did it finally blow in tesla's face? (Hint: find the resistivity of the bulb first and then use P=I^2*R or P=V^2 / R
Board
500
Kylo Ren pushed Finn off a cliff, and Rey tried to use force to prevent Finn from falling into sarlacc's monstrous mouth and certain death. Finn weights 100 Kilograms and the gravity on that planet is 10m/s/s. Rey knows that Finn has 8 coulombs of positive charge, and that Finn is 4 meters below her and 3 meters away. So, how many coulombs of negative charge must Rey generate on herself to create an attractive force to prevent Finn from falling further at that instant.
Gonna do it on the board...
500
What is the value and units of K without looking at your notes. Consider the formula Force= kq1q1/(r^2)
8.99x10^9 Nm^2/C^2
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