Mathematics
Mathematics
Problem
A long straight wire carries a current of . The magnetic field at a point 4 cm from the wire is . If the current is increased to and the observation point is moved to 8 cm from the wire, the new magnetic field will be a) b) c) d)Intuitive explanation
The magnetic field around a long straight wire depends on two things: how much current flows through it, and how far away you are. The key is recognizing that field strength is directly proportional to current but inversely proportional to distance—so doubling the current doubles the field, while doubling the distance cuts it in half. Use this relationship to compare the two scenarios without needing to calculate actual numbers.
Intuitive explanation
The magnetic field around a long straight wire depends on two things: how much current flows through it, and how far away you are. The key is recognizing that field strength is directly proportional to current but inversely proportional to distance—so doubling the current doubles the field, while doubling the distance cuts it in half. Use this relationship to compare the two scenarios without needing to calculate actual numbers.