Question

A length L of wire carries a steady current I. It is bent first to form a circular plane coil of one turn. The same length is now bent more sharply to give a double loop of smaller radius. The magnetic field at the centre caused by the same current is

[NCERT 1980

• A. A quarter of its first value
• B. Unaltered
• C. Four times of its first value
• D. A half of its first value

Answer 1

The correct option is C

Four times of its first value