Question

The resistivity of a 1.0 m long wire is 1.72 × 10-8 Om and its cross sectional area is 2.0 × 10-6 m2. If the wire carries a current of 0.20 A, what is the voltageacross the wire?


a) 10 mV
b) 17 mV
c) 0.90 mV
d) 1.7 mV
e) 90 mV

Answer 1

R = 1.72*10^-8*1/2*10^-6= 0.0086 ohm

V= 0.2*0.0086 = 0.0172 v

Answer 2

R= (1.72*10^-8* 1)/(2*10^-6) = 8.6*10^-3

V= I*R= 0.2*8.6*10^-3= 1.72*10^-3= 1.7 mv
d) 1.7 mV

Answer 3

c) 0.90 mV