Answer:
Output voltage is 1.92 volts.
Step-by-step explanation:
Given that,
Number of turns in primary coil,

Number of turns in secondary coil,

Input voltage,

We need to find the voltage output of a transformer used for rechargeable flashlight batteries. For a transformer, the number of turns and the voltage ratio is given by :

So, the output voltage is 1.92 volts.