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# Magnetic fields

2. A coil of wire carries current I flowing clockwise as shown in the figure. The outer circle is the current loop. If the observer could "see" the magnetic field inside this arrangement of loops, how would it appear?

(see attached file for diagrams)

3. A conducting loop of wire is placed in a magnetic field that is normal to the plane of the loop. Which one of the following actions will not result in an induced current in the loop?
a. Rotate the loop about an axis that is parallel to the field and passes through the center of the loop.
b. Increase the strength of the magnetic field
c. Decrease the area of the loop
d. Decrease the strength of the magnetic field
e. Rotate the loop about an axis that is perpendicular to the field and passes through the center of the loop

6. It is widely believed that a lightning bolt can cause a harmful current to flow in the circuit of an appliance, thereby damaging it. Which of the following is a true statement concerning this idea?

8. Two particles move through a uniform magnetic field that is directed out of the plane of the page. The figure shows the paths taken by the two particles as they move through the field. The particles are not subject to any other force in the field. The particles are not subject to any other forces or fields. Which one of the following statement concerning thse particles is true?

9. Five balls labelled A, B, C, D, and E are place in front of the plane mirror as shown in the figure. Which ball(s) will the observer see reflected in the mirror?

#### Solution Preview

2. Direction of magnetic field lines can be determined as follows : Curl the fingers of the right hand with the thumb stretched out such that the fingers point in the direction of the current flow. Then, the thumb gives the direction of the magnetic lines. In this case direction of the current in the coil is clockwise. Hence, direction of magnetic lines inside the coil will be into the plane of the coil.

See attached file for diagram.

As seen from the top, the field lines will be seen going into the plane of the coil (fig.(c)).

3. As per Faraday's law of electro-magnetic induction, no emf will be induced in the loop (hence, no current will flow) if there is ...

#### Solution Summary

The following posting addresses posting regarding magnetic fields. Step by step solutions provided.

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