Question

A copper rod PQ carrying current is kept in a magnetic field as shown in the diagram.

1. The copper rod PQ will move towards C. State True or False.
2. Name the law used to determine the direction of motion of PQ.
3. What will be the effect on the force experienced, if the rod PQ is replacedby another copper rod of same length but of greater cross-sectional area?
4. Justify your answer in (c).

Answer 1

a. This statement is true.

Explanation:

As the magnetic field is from upward to downward direction and the direction of current is from left to right, the rod PQ will experience a force towards C. So, PQ will move towards C.

b. Fleming’s left-hand rule.

c. The resistance of the substitute copper rod will be less than that of the original if it is the same length but has a larger cross-sectional area. As a result, the new rod will have a higher current than the old one. As a result, there will be more force felt.

d. As force experienced is directly proportional to the applied current, so if the current increases, then the force obviously increases.