What is the standard amperage for c batteries?

That will depend on a few things. The current output of the battery will depend on the operating voltage of the battery and the load resistance. If you know the load resistance and operating voltage, you can calculate the current using Ohm's Law. The Ohm's Law equation is I=V/R where "I" represents current in Amps, "V" represents voltage in volts and "R" represents resistance in ohms.

For a standard C battery, the operating voltage will start out at approximately 1.5 Volts but that voltage will decrease as charge is drained from the battery. The load resistance should remain constant so the current output of the battery will steadily decrease over time. You could use a multimeter to measure the voltage and load resistance across the terminals of the battery.

See the related link for a Duracell C battery datasheet for more details on how a battery would operate under standard usage conditions.