Question

A metal sphere has a charge of –6 mC. When 5 × 1012 electrons are removed from the sphere, what would be net charge on it?

Answer 1

`-"5.992 mC"`

Explanation:

• `"1 mC" = 10^-3\ "C"`
• `"1 μC" = 10^-6\ "C"`

Charge of `1` electron`= -1.6 × 10^-19\ "C"`

Charge of `5 × 10^12` electrons is

`5 × 10^12 cancel"electrons" × (-1.6 × 10^-19\ "C")/(1 cancel"electron") = -8 × 10^-7\ "C" = -"0.8 μC"`

After removal or electrons sphere attained a charge of `"+0.8 μC"`

Net charge`= -6\ "mC" + 0.8\ "μC" = -5.992\ "mC"`

`—————`

If sphere was initially charged with`bb(-"6 μC")` then

Net charge`= -6\ "μC" + 0.8\ "μC" = -"5.2 μC"`