Question

For the circuit on the right, find the following quantities:

a. The circuit current.

b. The total resistance of the circuit.

c. The value of the unknown resistance, R.

d. The voltage-drop across all resistors in the circuit.

e. The power dissipated by all resistors.

100Ω

150Ω

E=25V

Rt= 800Ω

30Ω

R

Answer 1

(1)

$I_t=\frac{V}{R_t}=\frac{25}{800}=0.03125A$

(2)

Net resistance

$R_{net}=800 \Omega$

(3)

$R_t=R_1+R_2+R_3+R_4$

$R_t=100+150+30+R$

$800=100+150+30+R$

$R=520\Omega$

(4)

$V_1=100\times0.03125=3.125\Omega$

$V_2=150\times0.03125=4.6875\Omega$

$V_3=30\times0.03125=0.9375\Omega$

$V_4=520\times0.03125=16.25\Omega$

(5) Power

$$P_1=i_1V_1=3.125\times0.03126=0.0976W$$

$$P_2=i_2V_2=4.6875\times0.03126=0.1465W$$

$$P_3=i_3V_3=0.9375\times0.03126=0.02930W$$

$$P_4=i_4V_4=16.25\times0.03126=0.5079W$$