How long will a current of 0.995 A need to be passed through water (containing H2SO4) for 5.00 L of O2 to be produced at STP

Iknow the answer is a but i don't know why

What produces wave a)sound b) heats c)transfer of energy d)vibrations

100 grams of molten lead (600°c) is used to make musket balls. if the lead shot is allowed to cool to room temperature (21°c), what is the change in entropy (in j/k) of the lead? (for the specific heat of molten and solid lead use 1.29 j/g⋅°c; the latent heat of fusion and the melting point of lead are 2.45 × 104 j/kg and 327°c, respectively.)