A1.4 v d-cell battery is rated at 15,000 ma⋅h. part a for how long could such a battery power a flashlight bulb rated at 1.1 w ?

The current through a 1.1 watts light bulb is given by the equation

Thus 
The capacity of the battery is 

In words we say that if a current of 15 A is taken from it, it lasts for 1 hour.
If we take a current I=0.786 A the battery lasts a time of 

  

 

Ais the answer hope this