Question

A typical rechargeable deep-cycle battery for an electric trolling motor (fishing boat) delivers 10A of current at a voltage of 12V for 10 hours. (a) How much charge (in coulombs) flows through the battery in this interval? (The answer is a positive value.) (b) How much energy (in joules) does the battery deliver? (The answer is a positive value.) (c) How much energy (in watt-hours) does the battery deliver? (The answer is a positive value.)

Answer 1

Answer:

a) 360 kQ

b) 4.32 MJ

c) 1200 W-h

Explanation:

a) The definition of the current is.

$I= \frac{Q}{t}$

having a count that 10 hours = 36.000 s

$Q = I*t$

$Q = 36000*10 = 360.000 [Q]$

b) The definition of the Energy in power terms is.

$E = \int\limits^{t}_{0} {P} \, dt$

and the definition of power is:

$P = V*I = 12 * 10 = 120 [W]$

replacing in the energy formula.

$E = \int\limits^{36.000}_{0} {120} \, dt$

solving the integral, have into account that t is in seconds.

$E=P*t=120*36000=4.320.000=4.32 [MJ]$

c) The energy in W-h, we can find it multiplying power by hours

$E = P*t =120*10 = 1200 W-h$.