Question

A small toy car draws a 0.50-mA current from a 3.0-V NiCd battery. In 10 min of operation, (a) how much charge flows through the toy car, and (b) how much energy is lost by the battery? 4. (Resistance and Ohm’s law, Prob. 17.16, 1.0 point) How

Answer 1

Answer:

(a) 0.3 C

(b) 0.9 J

Explanation:

(a)

Given:

Current drawn (I) = 0.50 mA = 0.50 × 10⁻³ A

Terminal voltage (V) = 3.0 V

Time of operation (t) = 10 min = 10 × 60 = 600 s

Charge flowing through the toy car 'Q' is given as:

$Q=It$

Plug in the given values and solve for 'Q'. This gives,

$Q=(0.50\times 10^{-3}\ A)(600\ s)\\\\Q=0.3\ C$

Therefore, 0.3 C charge flows the toy car.

(b)

Energy lost by the battery is equal to the product of power consumed by the battery and time of operation.

Power consumed by the battery is given as:

$P=VI$

Plug in the given values and solve for 'P'. This gives,

$P=(3.0\ V)(0.50\times 10^{-3}\ A)\\\\P=1.5\times 10^{-3}\ W$

Therefore, the energy lost by the battery is given as:

$E=P\times t\\\\E=1.5\times 10^{-3}\ W\times 600\ s\\\\E=0.9\ J$

Therefore, the energy lost by the battery is 0.9 J