Circuit Lab B/C

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Circuit Lab B/C

Post by azboy1910 » September 7th, 2020, 8:17 pm

Let's get this marathon started!

1. What is the capacitance of two parallel plates which are 5.3 mm apart, have an area of 30.4 mm^2 each, and have a dielectric constant of air between them (k = 1.0006)?
2. Three light bulbs are in series and connected to a battery. One of the light bulbs is disconnected. What will happen to the other bulbs?
3. A proton is moving east towards a magnetic field pointing upwards. What is the direction of the force exerted on the proton?
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Re: Circuit Lab B/C

Post by Krish2007 » September 8th, 2020, 2:58 pm

azboy1910 wrote:
September 7th, 2020, 8:17 pm
Let's get this marathon started!

1. What is the capacitance of two parallel plates which are 5.3 mm apart, have an area of 30.4 mm^2 each, and have a dielectric constant of air between them (k = 1.0006)?
2. Three light bulbs are in series and connected to a battery. One of the light bulbs is disconnected. What will happen to the other bulbs?
3. A proton is moving east towards a magnetic field pointing upwards. What is the direction of the force exerted on the proton?
1) 5.079 * 10^-11
2) All 3 light bulbs will turn off since it is an open circuit
3) North or upwards
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Re: Circuit Lab B/C

Post by azboy1910 » September 8th, 2020, 5:13 pm

Krish2007 wrote:
September 8th, 2020, 2:58 pm
azboy1910 wrote:
September 7th, 2020, 8:17 pm
Let's get this marathon started!

1. What is the capacitance of two parallel plates which are 5.3 mm apart, have an area of 30.4 mm^2 each, and have a dielectric constant of air between them (k = 1.0006)?
2. Three light bulbs are in series and connected to a battery. One of the light bulbs is disconnected. What will happen to the other bulbs?
3. A proton is moving east towards a magnetic field pointing upwards. What is the direction of the force exerted on the proton?
1) 5.079 * 10^-11
2) All 3 light bulbs will turn off since it is an open circuit
3) North or upwards
1. Make sure to give units next time in your answer. Also, make sure to round your answer to the least number of significant figures, which is two in this question (in 5.3 mm).

For this question, I was looking for the answer 5.1 x E-14 F.

Here's why I think so: 
Image

2. Correct

3. Using Fleming's right hand rule (since this is a proton), we can see that the force exerted on the proton is into the page, also represented by the following symbol:
Image

Please feel free to PM me if you see any mistake (s) in my explanation and/or work shown.
Your turn!
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Re: Circuit Lab B/C

Post by Krish2007 » September 9th, 2020, 9:17 am

You're right, I messed up my unit conversions on the first one.
Anyways,
1) Name a universal logic gate and explain what a universal logic gate is.
2) Briefly explain Kirchhoff's current law (the junction rule)
3) Determine the resistance between 2 points (a and b) if they are adjacent vertices of a regular tetrahedron. Assume that each edge of the tetrahedron has a resistance of one ohm.
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Re: Circuit Lab B/C

Post by Creationist127 » September 11th, 2020, 12:35 pm

Krish2007 wrote:
September 9th, 2020, 9:17 am
You're right, I messed up my unit conversions on the first one.
Anyways,
1) Name a universal logic gate and explain what a universal logic gate is.
2) Briefly explain Kirchhoff's current law (the junction rule)
3) Determine the resistance between 2 points (a and b) if they are adjacent vertices of a regular tetrahedron. Assume that each edge of the tetrahedron has a resistance of one ohm.
1. A gate that can implement a boolean operation without using any other gates, such as a NAND gate.
2. All the current going into a junction equals all the current leaving the junction; or, all the currents (with direction taken into consideration) add up to 0.
3. 0.5 Ω
2018: Hovercraft, Thermo, Coaster, Solar System
2019: Thermo, Circuit Lab, Sounds, Wright Stuff
2020: Circuit Lab, Wright Stuff, Machines
2021: Circuit Lab, Machines, WIDI, anything but Wright Stuff

Can I request that we delete 2020 from our memories and do it over again?

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Re: Circuit Lab B/C

Post by Krish2007 » September 11th, 2020, 3:05 pm

Creationist127 wrote:
September 11th, 2020, 12:35 pm
Krish2007 wrote:
September 9th, 2020, 9:17 am
You're right, I messed up my unit conversions on the first one.
Anyways,
1) Name a universal logic gate and explain what a universal logic gate is.
2) Briefly explain Kirchhoff's current law (the junction rule)
3) Determine the resistance between 2 points (a and b) if they are adjacent vertices of a regular tetrahedron. Assume that each edge of the tetrahedron has a resistance of one ohm.
1. A gate that can implement a boolean operation without using any other gates, such as a NAND gate.
2. All the current going into a junction equals all the current leaving the junction; or, all the currents (with direction taken into consideration) add up to 0.
3. 0.5 Ω
All 3 are correct, your explanations for Kirchhoff's current law and universal gates were better than I could have put it myself.

Your turn!
Beckendorff Junior High '21
2019-2020 events: Ornithology, Game On, Mission Possible, Circuit Lab
Game On is the best event!

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Re: Circuit Lab B/C

Post by Creationist127 » September 14th, 2020, 5:45 am

1. Suppose you have an RC circuit consisting of a 9 volt battery, a 5 microfarad capacitor, and a 5 kiloohm resistor.
a. Give the time constant for the circuit.
b. Assuming the capacitor starts completely discharged, how long would it take to have 1 volt across the capacitor? 4.5 volts?
c. How long would it take for the capacitor to completely charge?

2. Using the laws of Boolean algebra, simplify this expression as much as possible:
(A*B*C) + A*(!B+!C)

3. Give the resistance (including tolerance) of a resistor with the following bands:
a. Red, green, blue, gold
b. Brown, white, orange, silver
c. Yellow, black, red
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Can I request that we delete 2020 from our memories and do it over again?

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Re: Circuit Lab B/C

Post by azboy1910 » September 15th, 2020, 12:32 pm

Creationist127 wrote:
September 14th, 2020, 5:45 am
1. Suppose you have an RC circuit consisting of a 9 volt battery, a 5 microfarad capacitor, and a 5 kiloohm resistor.
a. Give the time constant for the circuit.
b. Assuming the capacitor starts completely discharged, how long would it take to have 1 volt across the capacitor? 4.5 volts?
c. How long would it take for the capacitor to completely charge?

2. Using the laws of Boolean algebra, simplify this expression as much as possible:
(A*B*C) + A*(!B+!C)

3. Give the resistance (including tolerance) of a resistor with the following bands:
a. Red, green, blue, gold
b. Brown, white, orange, silver
c. Yellow, black, red
1a. 0.025 s
1b. 0.0044 s for 1 volt across the capacitor. 0.0198 s for 4.5 volts across the capacitor.
1c. 0.0395 s

2. A?

3a. 25 megaohms, tolerance of 5%
3b. 19 kilohms, tolerance of 10%
3c. 4 kilohms 
Last edited by azboy1910 on September 15th, 2020, 12:33 pm, edited 1 time in total.
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Re: Circuit Lab B/C

Post by Creationist127 » September 16th, 2020, 5:37 am

azboy1910 wrote:
September 15th, 2020, 12:32 pm
Creationist127 wrote:
September 14th, 2020, 5:45 am
1. Suppose you have an RC circuit consisting of a 9 volt battery, a 5 microfarad capacitor, and a 5 kiloohm resistor.
a. Give the time constant for the circuit.
b. Assuming the capacitor starts completely discharged, how long would it take to have 1 volt across the capacitor? 4.5 volts?
c. How long would it take for the capacitor to completely charge?

2. Using the laws of Boolean algebra, simplify this expression as much as possible:
(A*B*C) + A*(!B+!C)

3. Give the resistance (including tolerance) of a resistor with the following bands:
a. Red, green, blue, gold
b. Brown, white, orange, silver
c. Yellow, black, red
1a. 0.025 s
1b. 0.0044 s for 1 volt across the capacitor. 0.0198 s for 4.5 volts across the capacitor.
1c. 0.0395 s

2. A?

3a. 25 megaohms, tolerance of 5%
3b. 19 kilohms, tolerance of 10%
3c. 4 kilohms 
1. a. is right, but I got .0029 s and .017s for b., and I was looking for infinite time or something similar for c., as in an ideal system the capacitor will only approach, and never reach, fully charged.
2 is right, 3. a. and b. are right. 3. c. the numbers are right, but I've always seen that no fourth band means a tolerance of 20%.

Which one of us did 1. b. and c. wrong?
Last edited by Creationist127 on September 16th, 2020, 5:38 am, edited 1 time in total.
2018: Hovercraft, Thermo, Coaster, Solar System
2019: Thermo, Circuit Lab, Sounds, Wright Stuff
2020: Circuit Lab, Wright Stuff, Machines
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Can I request that we delete 2020 from our memories and do it over again?

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Re: Circuit Lab B/C

Post by azboy1910 » September 16th, 2020, 7:43 am

Creationist127 wrote:
September 16th, 2020, 5:37 am
azboy1910 wrote:
September 15th, 2020, 12:32 pm
Creationist127 wrote:
September 14th, 2020, 5:45 am
1. Suppose you have an RC circuit consisting of a 9 volt battery, a 5 microfarad capacitor, and a 5 kiloohm resistor.
a. Give the time constant for the circuit.
b. Assuming the capacitor starts completely discharged, how long would it take to have 1 volt across the capacitor? 4.5 volts?
c. How long would it take for the capacitor to completely charge?

2. Using the laws of Boolean algebra, simplify this expression as much as possible:
(A*B*C) + A*(!B+!C)

3. Give the resistance (including tolerance) of a resistor with the following bands:
a. Red, green, blue, gold
b. Brown, white, orange, silver
c. Yellow, black, red
1a. 0.025 s
1b. 0.0044 s for 1 volt across the capacitor. 0.0198 s for 4.5 volts across the capacitor.
1c. 0.0395 s

2. A?

3a. 25 megaohms, tolerance of 5%
3b. 19 kilohms, tolerance of 10%
3c. 4 kilohms 
1. a. is right, but I got .0029 s and .017s for b., and I was looking for infinite time or something similar for c., as in an ideal system the capacitor will only approach, and never reach, fully charged.
2 is right, 3. a. and b. are right. 3. c. the numbers are right, but I've always seen that no fourth band means a tolerance of 20%.

Which one of us did 1. b. and c. wrong?
 
Ok, so this is how I came up with my answers for 1b.

1b. 1 V/(63.2% x 9 V) x 0.025 s = 0.0044 s, 4.5 V/(63.2% x 9 V) x 0.025 s = 0.0198 s

This is most likely wrong, but this is just how I got my answers.

1c. I think you are right for this one because capacitors never really accomplish being fully charged as you said, although very close.
Last edited by azboy1910 on September 16th, 2020, 7:45 am, edited 1 time in total.
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