Simplify : `[2^[1931]-2^[1930]]/2^[1930]`

Simplify : (a^2 – b^2)^2

Simplify: (2^(3))^(2)

Simplify: (a^2 - b^2)^2

Simplify (2)^((-2)(-2)

Simplify (a^2-b^2)^2

When electric current is passed through acidified water for 1930s, 1120 mL of H_(2) gas is collected (at STP) at the cathode. What is the current passed in ampere?