Question

A heart pacemaker fires 72 times a minute, each time a 25.0 - nF capacitor is charged (by a battery in series with a resistor) to 0.632 of its full voltage. What is the value of the resistance?

a) 2.45 × 1042
b) 3.20 × 1042Ω
c) 4.12 × 104
d) 5.33 × 1042Ω

Answer 1

The resistance value of the heart pacemaker is 2.45 × 10^4 Ω.

Step-by-step explanation:

The time constant of an RC circuit can be calculated using the formula: RC. In this case, we have a heart pacemaker that fires 72 times per minute and charges a 25.0-nF capacitor to 0.632 of its full voltage. The time for the capacitor to charge to 0.632 of its full voltage is known as one time constant. We can determine the time constant using the equation:

1 time constant = 1 / (72 times per minute)

To calculate the resistance, we can then use the formula:

R = time constant / C

Substituting the given values:

R = (1 / (72 times per minute)) / (25.0-nF)

After performing the calculations, the value of the resistance is 2.45 × 10^4 Ω.