the voltage and current doubles
it increases
it increases
You need to multiply the number of coulombs by the number of volts. If the two batteries are in series, then you can add the voltage of both batteries.
Before we can attempt an answer to that question, we'll need to agree on themeaning of the fuzzy, slippery phrase "amount of electricity". I'm going to interpretthat phrase to mean the current through the circuit.If the batteries are connected in series, then more batteries produce more currentthrough the circuit.If the batteries are connected in parallel, then the number of them has no effecton the magnitude of current through the circuit. But whatever the current is, morebatteries will cause it to flow in the circuit for a longer time, before they run down.
You can hook up an infinitive number of 12 volt batteries in a parallel circuit and still have 12 volts.
The number itself becomes double.
They double
The voltage stays the same as a single battery but the amperage multiplies by the number of batteries in the circuit. Example: Three 12 volt batteries with a CCA or 300 amps each wired together in parallel will produce 12 volts and 900 CCA.
If you double the amount of gas in the same volume you will double the pressure.
There are a number of different sources for the energy which moves electricity through a circuit. There are the power plants which have turbine generators and supply current to homes and businesses. There are batteries, which supply mobile devices such as cell phones. There are also photovoltaic cells, which can substitute for either turbines or batteries in some situations.
the volume doubles
Use rechargeable batteries. They can be recharged up to 200 times and they cost about double that of ordinary batteries.Use transformers to run your small appliances direct from the wall socket.