# A positively charged particle is moving in the + x direction shown in the above picut

## Homework Statement

I need help with question number 8 and 9. I have no idea where to start.

## Answers and Replies

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rl.bhat
Homework Helper

8) Point your right hand finger tips in the direction of the velocity of positive charge, bend the fingers in the direction of the field the thumb indicate the direction of the force.
9) Curl your right hand fingers. point your thumb in the direction of increasing field, then the direction of the finger tips indicates the direction of the current.

Is 8 letter C which is +Y? Also, for 9, I am not sure what you are talking about. Can you be more specific?

rl.bhat, for number 9 you are mistaken. What you said would be correct if we weren't dealing with the magnetic field "inducing" a current in the loop.

The answer would be B for #9. Since the magnetic field B is increasing into the page, the magnetic flux is changing through the loop. A changing magnetic flux induces a current in the loop that produces a magnetic field because current flow causes a magnetic field. This induced magnetic field wishes to resist the changing magnetic flux. Thus, the current will flow such that it causes a magnetic field to resist the increasing magnetic field. In this case, the induced magnetic field is pointing out of the page, to resist the field that is into the page, and current flows counterclockwise.

Ok thank you. I will review this tomorrow. Whjat was the answer to number 8?

rl.bhat
Homework Helper

rl.bhat, for number 9 you are mistaken. What you said would be correct if we weren't dealing with the magnetic field "inducing" a current in the loop.
Yes. My wording was wrong. It should have been "the direction of the induced increasing field".
Again we have specify what is increasing field? Whether north pole is approaching or south pole?

The answer to number 8 was C.

Increasing field means that the field is increasing in strength.