# Coulombs to Ampere-hours. Joules to Kilowatthours

#### George321

Coulombs are the usual unit of charge. Show that ampere-hours are an alternative unit.
Joules are the normal units for energy. Show that kilowatthours are an alternative.

#### songoku

Hi george

1. Do you know the formula relating charge, current, and time?
2. Do you know the formula relating energy, power, and time?

#### theophyman

hello george,
this my first post in this forum,

charge, time and current are related as follows:
I=dq/dt in other words : Ampere=coulomb/second
so we can write this:
coulomb=ampere * second
because hour=3600 second so charge (coulomb) can be expressed by ampere hour (ampere*hour)

puissane is energy per second , ie: puissance=energy/time
this leads to: energy=puissance * time
we know that the unit of energy is joul, the unit of puissance is watt, unit of time is second.
so joul can be expressed by watt second , or killowatt second , or as you asked killowatt hour

i hope i could explain it to you well (english is not my native language)(Bigsmile)

#### arbolis

PHF Hall of Fame
hello george,
this my first post in this forum,

charge, time and current are related as follows:
I=dq/dt in other words : Ampere=coulomb/second
so we can write this:
coulomb=ampere * second
because hour=3600 second so charge (coulomb) can be expressed by ampere hour (ampere*hour)

puissane is energy per second , ie: puissance=energy/time
this leads to: energy=puissance * time
we know that the unit of energy is joul, the unit of puissance is watt, unit of time is second.
so joul can be expressed by watt second , or killowatt second , or as you asked killowatt hour

i hope i could explain it to you well (english is not my native language)(Bigsmile)
Welcome to PHF.
You should read once again the part
Forum Rules said:
On helping with questions: Any and all assistance given to homework assignments or textbook style exercises should be given only after the questioner has shown some effort in solving the problem. If no attempt is made then the questioner should be asked to provide one before any assistance is given.
Songoku was trying to get George started. But with your full answer you just put songoku's help useless.
I hope it won't happen again. I do support your help, but not a full answer when the OP didn't show any work. Songoku's approach is in agreement with the rules while yours isn't. Thanks for your comprehension.

#### theophyman

thank you arbolis for the remark (Blush) .