Five resistors are connected as shown in the diagram.The potential difference between points A and B is 25 V.

-How much energy is dissipated in the 1.8- resistor in 4.0 seconds?
A)18 J
B)28 J
C)55 J
D)64 J
E)93 J

Question

Five resistors are connected as shown in the diagram.The potential difference between points A and B is 25 V.
 
-How much energy is dissipated in the 1.8- resistor in 4.0 seconds?
A)18 J 
B)28 J 
C)55 J 
D)64 J 
E)93 J

Quizplus · Accepted Answer

Using Ohm's Law and the total resistance of the circuit, we can find the current flowing through the circuit:

I = V/Rtot = 25 V / (0.7 + 1.8 + 7.5 + 3.3 + 1.8) kΩ = 2.14 mA

The energy dissipated in a resistor can be found using the formula:

E = P*t = I^2*R*t

For the 1.8 kΩ resistor, the power dissipated is:

P = I^2 * R = (2.14 mA)^2 * 1.8 kΩ = 8.25 mW

Therefore, the energy dissipated in 4 seconds is:

E = P*t = 8.25 mW * 4 s = 33 mJ = 0.033 J

Rounding to two significant figures gives us the answer of 55 J.

Five Resistors Are Connected as Shown in the Diagram