Question

A heart defibrillator is used to enable the heart to start beating if it has stopped. This is done by passing a large current of 12 A through the body at 25 V for a very short time, usually about 3.0 ms. (a) What power does the defibrillator deliver to the body, and (b) how much energy is transferred

Answer 1

Answer:

(a) 300 W

(b)0.90 J

Explanation:

(a) The electric power for any circuit element is given as

$P=IV$

Here I is current passing in the circuit and V is the voltage.

Given I = 12 A and V =25 V.

Substitute the given values, we get

$P=12 A \times25 V$

P = 300 W.

Thus, the power defibrillator deliver to the body is 300 W.

(b) To calculate the electric energy use the relation between electric energy, power and time as

$E=Pt$

Given t = 3 ms.

Substitute the values, we get

$E=300 W\times 3\times 10^-^3s$

E = 0.90 J.

Thus, the energy transferred is 0.90 J.