Electrostatics

Total atoms in the solid =6×1024
0.005% of atoms lose one electron each.
Step 1: Find how many atoms lose an electron
Number of affected atoms =(0.005%)×(6×1024)
0.005%=‌

0.005

100

=5×10−5
⇒ Number of atoms losing electrons =6×1024×5×10−5=3×1020
Step 2: Each atom loses one electron
Each lost electron corresponds to a positive charge gained by the solid equal to the charge of that electron (e=1.6×10−19C).
Step 3: Total charge gained
‌Q=(3×1020)×(1.6×10−19)
‌Q=4.8×101=48c