Mathematics

Problem

A long straight wire is stretched vertically along the North–South direction. A steady current of

8\,\text{A}

flows from South to North through the wire. a. (i) Point

P

is located

6\,\text{cm}

due West of the wire and in the same horizontal plane. State the direction of the magnetic field at

P

. b. (ii) Point

Q

is located

6\,\text{cm}

due East of the wire and lies in the same horizontal plane. State the direction of the magnetic field at

Q

. c. (iii) The current in the wire is now reversed while all positions remain unchanged. Write the new directions of the magnetic field at points

P

and

Q

. Give reasons for each answer.