What is the resistance of a 20.0-meter-long
tungsten rod with a cross-sectional area of
1.00 × 10^−4 meter2 at 20°c?
(1) 2.80 × 10^−5 ω (3) 89.3 ω
(2) 1.12 × 10^−2 ω (4) 112 ω

Option (2)

Explanation:

The resistance of a conductor is directly proportional to the length of the conductor and inversely proportional to the area of the conductor. The formula for the resistance is given by

Where, ρ is the resistivity of tungsten, l be the length of tungsten and a be the area of cross section.

The value of resistivity for tungsten is 5.6 x 10^-8 ohm metre.

12000j is work done

d₁ = displacement of tern from arctic to antarctic = 11000 miles

d₂ = displacement of tern from antarctic to arctic =   - 11000 miles

d = total displacement for the journey

total displacement for the journey is given as

d = d₁ + d₂

d = 11000 + (-11000)

d = 0 miles

t₁ = time of travel from arctic to antarctic = 3 months = 3 x 30 days = 90 days

t₂ = time of travel from antarctic to arctic = 3 months = 3 x 30 days = 90 days

t = total time of travel

total time of travel is given as

t = t₁ + t₂

t = 90 + 90

t = 180 days

average velocity is given as

average velocity = total displacement/ total time

v = d/t

v = 0/180

v = 0 miles/day