Find the magnitude of momentum of electrons in a straight wire of copper of length 1 meter carrtying a current of 16 ampere.
a) 14.56e-12 kg m/s
b) 29.12e-12 kg m/s
c) 18.2e-11 kg m/s
d) 91e-12 kg m/s
The answer is (d)
The Attempt at a Solution
16 A = 16C/s
16 A = 16 * ( 6e+18 ) electrons/s [ 1 C = 6e+18 electrons ]
mass of 96e+18 electrons/s = 9.1e-31 * 96e+18
= 8.73e-11 kg/s
Since the only unit left is meter and there is only quantity of meter(1 meter), i just multiply it to make the unit of momentum.
so i get the answer as 8.73e-11 kg m/s, which is the closest to the right answer.
But this doesnt really seem to make sense, isnt there some other way? The value for mass of an electron is also not given in our textbook.