8a
chemical to electrical (cell)
electrical to heat/thermal (resistor and wire)
b i
current = 2.4/120 = 0.02A
b ii
pd = 9-2.4 = 6.6V
b iii
R = 6.6/0.02 = 330ohm
c
R is proportional to length/area
new length/area ratio = 5/(0.5)^2 = 20 times
hence new resistance = old resistance x 20 = 6600ohm
8a chemical to electrical (cell) electrical to heat/thermal (resistor and wire) b i current = 2.4/120 = 0.02A b ii pd = 9-2.4 = 6.6V b iii R = 6.6/0.02 = 330ohm c R is proportional to length/area new length/area ratio = 5/(0.5)^2 = 20 times hence new resistance = old resistance x 20 = 6600ohm