Question

a) Determine the SI base units of resistivity (10 marks)
b) A car headlight filament is made of tungsten and has a cold resistance of 0.350 Ω. If the filament is a cylinder 4.00 cm long, what is its diameter? (8 marks)
c) Two charges Q1 &Q2 are separated by a distance D. If both charges are doubled, and distance is increased to 2D, what happens to the force between the charges? Show your work. (7 marks)

Answer 1

• The electrical resistivity is the electrical resistance per unit length and per unit of cross-sectional area at a specified temperature. The SI unit of electrical resistivity is the ohm⋅metre (Ω⋅m). It is commonly represented by the Greek letter ρ, rho.