# Line of action of force in torque experienced by a current loop

• logearav
In summary, the conversation discusses the concept of equal and opposite forces and their line of action, specifically in relation to a loop. It is mentioned that while F1 and F2 have the same line of action and result in a zero effect on the loop, F3 and F4 have different lines of action and create a couple force that can cause rotation. The direction of rotation is determined by the right-hand rule.
logearav

## Homework Equations

In the diagram, F1 and F2 are equal and opposite also F3 and F4 also equal and opposite.
Its been mentioned that F1 and F2 have same line of action of force and the resultant effect on the loop is zero. But F2 and F4 have different line of action and hence constitute a couple.

## The Attempt at a Solution

I have drawn lines of action for F1 and F2, F2 and F4 in dotted line in red colours. I can't find any difference between F1 and F2 , F2 and F4. Both are straight lines. So in what way the lines of action of F2 and F4 are different and how do they constitute a couple?
2) What is the rule that i has to apply to find the direction of force, in this case?
I mean why all the forces are directed outwards to the loop?

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. A:F1 and F2 are equal and opposite, so their line of action is the same. F3 and F4 also have equal and opposite force, but their line of action is different. If you draw a vector from the point where F3 is applied to the point where F4 is applied, then you have a couple force, which tends to rotate the loop. The direction of rotation is determined by the right-hand rule.

## 1. What is the line of action of force in torque experienced by a current loop?

The line of action of force in torque experienced by a current loop refers to the imaginary line along which the net force acts on the loop due to the presence of a magnetic field. This line is perpendicular to both the direction of the current in the loop and the direction of the magnetic field.

## 2. How is the line of action of force determined in a current loop?

The line of action of force in a current loop can be determined by using the right-hand rule. This rule states that if the thumb of the right hand is pointed in the direction of the current in the loop, and the fingers are pointed in the direction of the magnetic field, then the palm will face the direction of the net force on the loop.

## 3. What factors affect the line of action of force in a current loop?

The line of action of force in a current loop is affected by the strength of the current, the strength and direction of the magnetic field, and the orientation of the loop with respect to the field. Any changes in these factors can result in a change in the line of action of force.

## 4. How does the line of action of force in a current loop relate to the production of torque?

The line of action of force in a current loop is directly related to the production of torque. Torque is the product of the net force and the perpendicular distance from the line of action of force to the axis of rotation. Therefore, the closer the line of action of force is to the axis of rotation, the greater the torque produced by the loop.

## 5. Can the line of action of force change in a current loop?

Yes, the line of action of force in a current loop can change if there are changes in the factors that affect it, such as the current, magnetic field, or orientation of the loop. Additionally, if the loop is not in a uniform magnetic field, the line of action of force may vary at different points along the loop.

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