Variables and parameter DEFINITIONS and SAFETY: 1. Most cloud-to-ground lightnin
ID: 2991135 • Letter: V
Question
Variables and parameter DEFINITIONS and SAFETY: 1. Most cloud-to-ground lightning neutralizes (positive / negative) charges in the base of the cloud and (positive / negative) charges induced on the ground beneath the cloud. (circle one choice from each pair) 2. Lightning is most accurately modeled as a(n) a. independent voltage source. c. variable capacitor. b. independent current source. d. op-amp. 3. If a 30 kA lightning with a rise time of 10 mu s strikes a building with a grounding inductance of 35 mu H, find the largest allowable grounding resistance that will limit the voltage rise to 500 kV. 4. As the level of current flowing through the human body increases, various organs are affected in different ways. Choose the proper order in which the following organs are affected, in order from lowest current to highest current. a. heart fibrillates, diaphragm paralyzed, skeletal muscles contract, organ burns b. diaphragm paralyzed, heart fibrillates, organ burns, skeletal muscles contract c. organ bums, diaphragm paralyzed, skeletal muscles contract, heart fibrillates d. skeletal muscles contract, diaphragm paralyzed, heart fibrillates, organ bums 5. Ionizing radiation is especially dangerous to living cells because it a. damages DNA which can lead to cancer. b. prevents cells from reproducing. 6. Arc flash thermal energy can be reduced by c. makes cells smaller. d. destroys the cell's ability to take in nutrients. a. increasing the voltage at the point of the fault. b. increasing the fault current. c. reducing the impedance of the system. d. decreasing the operating time of the fault clearing device.Explanation / Answer
1. Most cloud to ground lightening neutralizes negative charges in the base of the cloud and positive charges induced on the ground beneath the cloud.
2. Independent current source
3. V=IR+L(dI/dt)
use your 500,000v as your V
use your 30,000A as your I
use your 35E-6H as your L
use your 30,000A/10E-6s as your dI/dt (or "rise time")
therefore 500,000v = (30,000)R + 35E-6H(30,000A/10E-6s)
where R = 13.16 ohms
4. skeletal muscles contract, diaphragm paralyzed, heart fibrillates, organ burns
5. damages DNA which can lead to cancer
6. decreasing the operating time of the fault clearing device
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.