How many excess electrons must be present on each sphere if the magnitude of the force of repulsion between them is 3.33×10−21 n?

The number of excess electrons on each sphere is 759

Explanation:

Given that,

distance , d = 20 cm

                    = 0.20 m

let the number of electrons is n  

Electric force (F) = k × (n × e)² /d²

3.33 × = 9 × × (n × 1.602 × )² /0.2²

solving for n

n = 759

an ion is a charged atom or molecule. it is charged because the number of electrons do not equal the number of protons in the atom or molecule. an atom can acquire a positive charge or a negative charge depending on whether the number of electrons in an atom is greater or less then the number of protons in the atom.

d₁ = displacement of tern from arctic to antarctic = 11000 miles

d₂ = displacement of tern from antarctic to arctic =   - 11000 miles

d = total displacement for the journey

total displacement for the journey is given as

d = d₁ + d₂

d = 11000 + (-11000)

d = 0 miles

t₁ = time of travel from arctic to antarctic = 3 months = 3 x 30 days = 90 days

t₂ = time of travel from antarctic to arctic = 3 months = 3 x 30 days = 90 days

t = total time of travel

total time of travel is given as

t = t₁ + t₂

t = 90 + 90

t = 180 days

average velocity is given as

average velocity = total displacement/ total time

v = d/t

v = 0/180

v = 0 miles/day