What is the number of free electrons in a piece of silver of cross-section 1.0 x 10-4 m2 and length 1m? Atomic weight of silver = 108, density of silver = 105 x 102 kg m-3. Assume that there is one free electron per atom.
Area, A = 1.0 x 10-4 m2
Atomic weight = 108
Volume of given piece = A x l = 1.0 x 10-4 m2 x 1m = 10-4 m3
Number of atoms in 108 kg silver = 6.023 x 1026
Since there is only free electron per atom, therefore the number of free electrons is 5.856 x 1024.
