Fraction of Electrons Removed
A copper slab of mass 2 g contains ` 2 xx 10 ^(22)` atoms. The charge on the nucleus of each atom is 29e. What fraction of the electrons must be removed from the sphere to give it a charge of `+2 muC ` ?

Explanation

Total number of electrons in the slab `= 29 xx 2 xx 10 ^(22)`
` therefore ` Number of electrons removed
` " " = (q)/(e) = ( 2 xx 10 ^(-6))/(16 xx 10 ^(-19)) " " (" given " ,q = 2muC = 2 xx 10 ^(-6) C) `
` " " = 1.25 xx 10 ^(13)`
` therefore ` Fractions of electrons removed
` " " = (" Number of electrons removed ")/(" Total number of electrons in the slab ") `
` = (1.25 xx 10 ^(13))/(29 xx 2 xx 10 ^(22)) = 2.16 xx 10 ^(-11)`