Question

The battery for a certain cell phone is rated at 3.70 V. According to the manufacturer it can produce math]3.15 \times 10^{4} J[/math] of electrical energy, enough for 5.25 h of operation, before needing to be recharged. Find the average current that this cell phone draws when turned on.

Answer 1

Answer:

The average current that this cell phone draws when turned on is 0.451 A.

Explanation:

Given;

voltage of the phone, V = 3.7 V

electrical energy of the phone battery, E = 3.15 x 10⁴ J

duration of battery energy, t = 5.25 h

The power the cell phone draws when turned on, is the rate of energy consumption, and this is calculated as follows;

$P = \frac{E}{t}$

where;

P is power in watts

E is energy in Joules

t is time in seconds

$P = \frac{3.15*10^4}{5.25*3600s} = 1.667 \ W$

The average current that this cell phone draws when turned on:

P = IV

$I = \frac{P}{V} =\frac{1.667}{3.7} = 0.451 \ A$

Therefore, the average current that this cell phone draws when turned on is 0.451 A.