Five amperes for two hours
Ten amperes for one hour
In other words, the result obtained by multiplying the number of amperes by the time in hours is the ampere hour capacity.
A dynamo must have an E. M. F. of about ten volts in order to charge a three-cell storage battery.
CHAPTER V ELECTRO-MAGNETISM AND MAGNETIC INDUCTION
Connect two copper wires to a voltaic cell and stretch a portion of the wire over a compass needle, holding it parallel to it and as near as possible without touching. Then bring the free ends of the wires together and observe that the needle is deflected and after a few movements back and forth comes to rest at an angle with the wire.
Fig. 76.—A Current of Electricity flowing through a Wire will deflect a Compass Needle.
Next form a rectangular loop of wire and place the needle within it as in Figure 77. A greater deflection will now be obtained. If a loop of several turns is formed, the deflection will be still greater.