## Circuit Lab B/C

Test your knowledge of various Science Olympiad events.
azboy1910
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### Re: Circuit Lab B/C

Alright,

1. Explain how an inductor functions in a circuit.
2. A 7-volt battery is in series with a 2.5k-ohm resistor and a 55 mF capacitor, forming an RC circuit. How long will it take for the capacitor to be charged to 3.2 volts? What is the charge on the capacitor at this state?
3. At the peak of a standard AC U.S. graph, what is the voltage?
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### Re: Circuit Lab B/C

azboy1910 wrote:
October 25th, 2020, 11:51 am
Alright,

1. Explain how an inductor functions in a circuit.
2. A 7-volt battery is in series with a 2.5k-ohm resistor and a 55 mF capacitor, forming an RC circuit. How long will it take for the capacitor to be charged to 3.2 volts? What is the charge on the capacitor at this state?
3. At the peak of a standard AC U.S. graph, what is the voltage?
1. It acts to resist changes in current by providing back EMFs through Faraday's law.
2. $3.2 = 7\left(1-e^{-\frac{t}{2500\cdot0.055}}\right)$, $t = 84\,\mathrm{s}.$
$Q = CV = 0.055 \cdot 3.2 = 0.18\,\mathrm{C}.$
3. 60root2 V? Is this for household application or high-voltage wires?


azboy1910
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### Re: Circuit Lab B/C

UTF-8 U+6211 U+662F wrote:
October 25th, 2020, 1:38 pm
azboy1910 wrote:
October 25th, 2020, 11:51 am
Alright,

1. Explain how an inductor functions in a circuit.
2. A 7-volt battery is in series with a 2.5k-ohm resistor and a 55 mF capacitor, forming an RC circuit. How long will it take for the capacitor to be charged to 3.2 volts? What is the charge on the capacitor at this state?
3. At the peak of a standard AC U.S. graph, what is the voltage?
1. It acts to resist changes in current by providing back EMFs through Faraday's law.
2. $3.2 = 7\left(1-e^{-\frac{t}{2500\cdot0.055}}\right)$, $t = 84\,\mathrm{s}.$
$Q = CV = 0.055 \cdot 3.2 = 0.18\,\mathrm{C}.$
3. 60root2 V? Is this for household application or high-voltage wires?

1. Correct
2. Correct
3. I'm sorry for not being clear on this, this is for household applications, and not when the voltage is tens of thousands of volts before the use of step-down transformers.
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UTF-8 U+6211 U+662F
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### Re: Circuit Lab B/C

azboy1910 wrote:
October 25th, 2020, 3:59 pm
UTF-8 U+6211 U+662F wrote:
October 25th, 2020, 1:38 pm
azboy1910 wrote:
October 25th, 2020, 11:51 am
Alright,

1. Explain how an inductor functions in a circuit.
2. A 7-volt battery is in series with a 2.5k-ohm resistor and a 55 mF capacitor, forming an RC circuit. How long will it take for the capacitor to be charged to 3.2 volts? What is the charge on the capacitor at this state?
3. At the peak of a standard AC U.S. graph, what is the voltage?
1. It acts to resist changes in current by providing back EMFs through Faraday's law.
2. $3.2 = 7\left(1-e^{-\frac{t}{2500\cdot0.055}}\right)$, $t = 84\,\mathrm{s}.$
$Q = CV = 0.055 \cdot 3.2 = 0.18\,\mathrm{C}.$
3. 60root2 V? Is this for household application or high-voltage wires?

1. Correct
2. Correct
3. I'm sorry for not being clear on this, this is for household applications, and not when the voltage is tens of thousands of volts before the use of step-down transformers.
3. 20 root 2 V? I have no idea

azboy1910
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### Re: Circuit Lab B/C

UTF-8 U+6211 U+662F wrote:
October 25th, 2020, 4:22 pm
azboy1910 wrote:
October 25th, 2020, 3:59 pm
UTF-8 U+6211 U+662F wrote:
October 25th, 2020, 1:38 pm
1. It acts to resist changes in current by providing back EMFs through Faraday's law.
2. $3.2 = 7\left(1-e^{-\frac{t}{2500\cdot0.055}}\right)$, $t = 84\,\mathrm{s}.$
$Q = CV = 0.055 \cdot 3.2 = 0.18\,\mathrm{C}.$
3. 60root2 V? Is this for household application or high-voltage wires?

1. Correct
2. Correct
3. I'm sorry for not being clear on this, this is for household applications, and not when the voltage is tens of thousands of volts before the use of step-down transformers.
3. 20 root 2 V? I have no idea
For question 3, the answer is 170 volts.
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### Re: Circuit Lab B/C

Around how many amps must flow through the heart in order to cause ventricular fibrillation (and death)? What are three ways to reduce this possible current when working with high voltage applications?

Creationist127
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### Re: Circuit Lab B/C

UTF-8 U+6211 U+662F wrote:
October 25th, 2020, 4:48 pm
Around how many amps must flow through the heart in order to cause ventricular fibrillation (and death)? What are three ways to reduce this possible current when working with high voltage applications?
.075 amps, or 75 mA. To reduce it, wear nonconductive PPE (e.g. rubber boots and gloves), make sure anything you touch is not "hot" (charged or connected to power), and don't work with electricity when you're wet.
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

Creationist127 wrote:
October 30th, 2020, 7:43 am
UTF-8 U+6211 U+662F wrote:
October 25th, 2020, 4:48 pm
Around how many amps must flow through the heart in order to cause ventricular fibrillation (and death)? What are three ways to reduce this possible current when working with high voltage applications?
.075 amps, or 75 mA. To reduce it, wear nonconductive PPE (e.g. rubber boots and gloves), make sure anything you touch is not "hot" (charged or connected to power), and don't work with electricity when you're wet.

Creationist127
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### Re: Circuit Lab B/C

1. A capacitor has 1 cm^2 plates, .5 mm apart from each other (with nothing in between). What is its capacitance?
2. A resistor is a cylinder with 5 mm diameter and is 1 cm long, and has resistivity 1 Ω*m. What is its resistance?
3. The resistor and capacitor are placed in series with each other and a 9-volt battery. How long will it take for the capacitor to charge to 8.5 volts?

EDIT: Fixed wording
Last edited by Creationist127 on November 5th, 2020, 9:20 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
2021: Circuit Lab, Machines, WIDI, anything but Wright Stuff

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

azboy1910
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### Re: Circuit Lab B/C

Creationist127 wrote:
November 4th, 2020, 7:24 am
1. A capacitor has 1 cm-square plates, .5 mm apart from each other (with nothing in between). What is its capacitance?
2. A resistor is a cylinder with 5 mm diameter and is 1 cm long, and has resistivity 1 Ω*m. What is its resistance?
3. The resistor and capacitor are placed in series with each other and a 9-volt battery. How long will it take for the capacitor to charge to 8.5 volts?
1. 1.77E(-10) F or 0.177 nF
2. 509.3 ohms
3. about 2.89 time constants
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