contestada

Two 1.50-V batteries—with their positive terminals in the same direction—are inserted in series into the barrel of a flashlight. One battery has an internal resistance of 0.240 Ω, the other an internal resistance of 0.180 Ω. When the switch is closed, a current of 600 mA occurs in the lamp. (a) What is the bulb's resistance? Ω (b) What fraction of the chemical energy transformed appears as internal energy in the batteries? %

Respuesta :

Lanuel

a. The resistance of the bulb is equal to 4.58 Ohms.

b. The fraction of the chemical energy transformed which appears as internal energy in the batteries is 8.4%.

Given the following data:

  • Voltage of battery = 1.5 Volts
  • Internal resistance A = 0.240 Ohms
  • Internal resistance B = 0.180 Ohms
  • Current = 600 mA = 0.6 Amps

a. To find the resistance of the bulb:

First of all, we would determine the total electromotive force (E) of the electric circuit:

[tex]E = 2 \times 1.50[/tex]

E = 3.0 Volts

Total internal resistance = [tex]0.240 + 0.180 = 0.42 \;Ohms[/tex]

Mathematically, electromotive force (E) is given by the formula:

[tex]E = V + Ir[/tex]    ....equation 1.

Where:

  • E is the electromotive force (E).
  • V is the the voltage or potential difference.
  • I is the current.
  • r is the internal resistance.

According to Ohm's law, voltage is given by:

[tex]V = IR[/tex]    ....equation 2

Substituting eqn 2 into eqn 1, we have:

[tex]E = IR + Ir\\\\E = I(R + r)\\\\R + r = \frac{E}{I} \\\\R = \frac{E}{I} - r\\\\R = \frac{3}{0.6} - 0.42\\\\R = 5 - 0.42[/tex]

Resistance, R = 4.58 Ohms

b. To determine what fraction of the chemical energy transformed appears as internal energy in the batteries:

First of all, we would determine the electromotive force (E) in the batteries.

[tex]E_B = IR\\\\E_B = 0.6 \times 0.42[/tex]

[tex]E_B[/tex] = 0.252 Volt

[tex]Percent = \frac{E_B}{E} \times 100\\\\Percent = \frac{0.252}{3} \times 100\\\\Percent = \frac{25.2}{3}[/tex]

Percent = 8.4 %

Read more: https://brainly.com/question/15121836

Otras preguntas