Plzz help. me with both questions

Explanation:

Primary cell    

1. They are non-rechargeable.

2. The energy density of primary cells is more.

3. The internal resistance of primary cells is more.

4. Example : Zinc-Carbon cell.

Secondary cells

1. They are rechargeable cells.

2. The energy density of secondary cells is less.

3. The internal resistance of secondary cells is less.

4. Example : Car batteries

Current :

The flow of electric charge per unit time is called electric current. It can be given by the formula as follows :

The SI unit of electric current is Ampere.

1 Ampere is defined as the current that flows with the electric charge of one Coulomb per second (C/s).

one "light year" is the distance that light travels, through vacuum, in one julian year.   that's 365.25 days, of 24 hours each.