Question

1. Answer A-D having to do with Ohm's Law:

A. What is the resistance of a toaster if 111 V produces a current of 4.28 A?

B. What voltage will produce 0.45 A of current through a 4996 Ω resistor?

C. What is the current in the element of an electric clothes dryer with a resistance of 8.86 Ω when it is connected to 243 V?

D. What is the resistance of a 13.00 m length of copper wire 2.0 mm in diameter? (ρ_copper = 1.68×10^-8 Ω.m)

Answer 1

(A) from Ohm's law

V = I*R

R = V/I = 111 / 4.28 = 25.9 Ohm

(B) the voltage through the current is

V = I*R = 0.45*4996 = 2248.2 V

(C) from Ohm's law

V =I*R

I = V/R = 243/8.86 = 27.4 A

(D) R = (rho *L)/ A

A = pi*r^2 = (3.14)(2/2 mm)^2 = 0.00000314 m

R = (1.68×10^-8)*(13) / (0.00000314)

= 0.0695 Ohm