# Find power dissipated in circuit with a ground

• physics416
In summary: V = I(18V) I=0.5 P = I^2 * R = 0.5^2 * 12 = 3 watts But, the ground doesn't change anything. In summary, the power dissipated by the 12 ohm resistor is 3 watts, and the potential at points a, b, c, d are all consistent and do not change due to the ground.
physics416

## Homework Statement

1. Find the power dissipated by 12 ohm resistor
2. What is the potential at points a,b,c,d?

P=I^2R
I=V/R

## The Attempt at a Solution

For a) 3v-IR-6v-IR=0
9v=I(18)
I=0.5
P=0.5^2 * 12 = 3 watts
But not sure if the ground changes anything

b) unsure if ground changes anything

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Hint : What is the voltage btw point b,a and b,c and a,d ? Groud represents 0V

Between bc is 6v and between ad is 3v? if my current calculation is correct, then is v between ab is 3? But are those the potential differences or the actual potentials? For example does the 6 ohm resistor use up all its potential such that it is 0 at point b and point c gains 6v?

Noctisdark said:
Hint : What is the voltage btw point b,a and b,c and a,d ? Groud represents 0V

Between bc is 6v and between ad is 3v? if my current calculation is correct, then is v between ab is 3? But are those the potential differences or the actual potentials? For example does the 6 ohm resistor use up all its potential such that it is 0 at point b and point c gains 6v?

Edit : for mistakes, Vad = 3V, Va = 0 since it's connected to the ground so Vd = 3, Vbc = 6V just as you said, according to your calculation P = RI^2 = V^2/R = 3, you're almost there !,

Last edited:
physics416 said:

## Homework Statement

1. Find the power dissipated by 12 ohm resistor
2. What is the potential at points a,b,c,d?

P=I^2R
I=V/R

## The Attempt at a Solution

For a) 3v-IR-6v-IR=0
9v=I(18)
I=0.5
P=0.5^2 * 12 = 3 watts
But not sure if the ground changes anything

b) unsure if ground changes anything

The ground changes nothing.

physics416 said:
b) unsure if ground changes anything

The "ground" means that the potential is zero at point a. But that does not change the potential differences between two points of the circuit.

physics416 said:
For a) 3v-IR-6v-IR=0

You got the right answer but this equation is inconsistent.

+3v implies you are summing the voltages anticlockwise so to be consistent it should be +6v not -6V...

+3V - (I*12) +6V - (I*6) = 0

## What is power dissipation in a circuit?

Power dissipation refers to the amount of energy that is converted into heat in a circuit. This is often caused by resistive elements in the circuit that convert electrical energy into heat.

## Why is power dissipation important in a circuit?

Power dissipation is important to consider in a circuit because it can affect the overall performance and reliability of the circuit. Excessive heat can cause damage to components and decrease the efficiency of the circuit.

## How is power dissipation calculated?

Power dissipation can be calculated by multiplying the voltage across a component by the current flowing through it. This can be represented by the equation P = VI, where P is power, V is voltage, and I is current.

## What is the role of a ground in power dissipation?

A ground in a circuit serves as a reference point for voltage and helps to regulate the flow of current. In terms of power dissipation, a ground can help to dissipate excess heat and maintain a safe operating temperature for the circuit.

## How can power dissipation be minimized in a circuit?

Power dissipation can be minimized by using components with lower resistance, reducing the overall power consumption of the circuit, and implementing proper heat dissipation techniques such as heat sinks and fans. It is also important to design the circuit with proper voltage and current ratings to prevent excessive power dissipation.

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