What is the twenty-minute rating of battery?
(a) Rate of current for 20 minutes with a minimum cell voltage of 1.5 V
(b) Time for which the battery can supply 25 A at 80℉ with minimum cell voltage 1.75 V
(c) The current which the battery can supply continuously for 30 seconds with minimum cell voltage 1.2 V
(d) Lasting power of a battery on a small load
The question was asked in a national level competition.
This is a very interesting question from Storage Batteries in chapter Nonconventional Engines, Conventional Energy Sources & Cooling System of Automobile Engineering