A lightning bolt strikes one end of a steel lightning rod, producing a 13800-A c

Question

A lightning bolt strikes one end of a steel lightning rod, producing a 13800-A current burst that lasts for 53s. The rod is 2.7-m long and 2.3-cm in diameter. Its other end is connected to the ground by 32-m of 10.3-mm-diameter copper wire. Copper: =1.72x10-8 ·m Steel: =20x10-8 ·m

PART A)

Find the potential difference between the top of the steel rod and the lower end of the copper wire during the current burst.

PART B)

Find the total energy deposited in the rod and wire by the current burst.

Hint #1: Total potential difference will be potential difference of steel rod plus potential differnce of copper wire.

Explanation / Answer

We know, R = rho*L/A

R_stell = R1 = 20*10^-8*2.7)/(pi*0.023^2/4) = 0.0012997

= 1.29*10^-3 ohms

R_copper= R2 = 1.71*10^-8*32/(pi*0.0103^2/4) = 0.00656

= 6.56*10^-3 ohms

Rnet = R1 + R2

= 1.29 + 6.56

= 7.85*10^-3 ohms

a) V = I*Rnet

= 13800*7.85*10^-3

= 108.33 volts

b) energy deposited, E = Power*time

= V*I*t

= 108.33*13800*53*10^-6

= 79.23 J

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.