Lithium polymer batteries have revolutionized the battery field due to their light weight,high energy density (about four times greater than nickel-cadmium or nickel-metal-hydride cells)and low internal resistance.At 25 $\circ$ C a three cell lithium polymer battery has no load voltage of 11.1 V and an internal resistance of 300 m$\varOmega$.If the battery is used to power a device that needs a minimum of 10.0 V,e.g.,it will not work if the applied voltage is below 10.0 V,what is the minimum resistance of that device?
A)1.35 $\varOmega$
B)2.43 $\varOmega$
C)2.73 $\varOmega$
D)3.03 $\varOmega$
E)4.62 $\varOmega$

Question

Quizplus · Accepted Answer

To find the minimum resistance of the device, we need to use Ohm's Law:

V = IR

where V is the minimum required voltage (10.0 V), I is the current flowing through the device, and R is the minimum resistance of the device.

We can find the maximum current that the battery can provide using its internal resistance:

I = V/R_internal

I = 11.1 V/300 mΩ

I = 37 A

Now we can find the minimum resistance of the device:

R = V/I

R = 10.0 V/37 A

R = 2.73 Ω

Therefore, the minimum resistance of the device is 2.73 Ω, which corresponds to choice C.

Lithium Polymer Batteries Have Revolutionized the Battery Field Due to Their