Question

Two AAA-size lithium batteries are connected in series in a flashlight. Each battery has 3.5 volt and 4- Amp-hour capacity. If the flashlight is connected to a light bulb with 10 Ohms resistance. How long does it take to drain the batteries?

Answer 1

Answer:

t= 9.79 hr

Explanation:

Given that

V= 3.5 V

Capacity= 4 Amp-hour

We know that

V= IR

V= Voltage

I =Current

R=Resistance

V = I R

The total voltage on the  batteries will be  2 V

2 x 3.5 = I x 10

I= 0.7 A

We know that Power P

P = V I

P = 0.7 x 7

P =4.9 W

4 A.h and 12 volt power supply = 4 x 12 = 48 W.hr

So time of drain t

4.9 t = 48

t= 9.79 hr