Final answer:
The two metals in a battery have opposite charges due to the chemical reactions that take place, with the anode being negative and the cathode being positive. This separation of charge is consistent with the conservation of charge in a closed circuit where equal electrons flow from the anode to the cathode.
Step-by-step explanation:
The correct answer to the question about the metals used in batteries is that c) The two metals have opposite charges. In a battery, chemical reactions occur at the electrodes (the two metals), producing a flow of electrons from the anode to the cathode. Specifically, electrons are placed on the anode, making it negative, while the cathode becomes positively charged because it has lost electrons. This process creates a separation of charge between the two metals, with the anode having a negative charge and the cathode having a positive charge.
A key point to understand is that in a closed circuit, the conservation of charge principle states that the number of electrons leaving one end of the battery (the anode) will be equal to the number of electrons entering the other end (the cathode). This is because electrons flow from the negative terminal to the positive terminal to complete the circuit and in the process, drive the electronic devices they power.