Question
Physics Question on Uniform Circular Motion
A thin stiff insulated metal wire is bent into a circular loop with its two ends extending tangentially from the same point of the loop. The wire loop has mass 𝑚 and radius 𝑟 and it is in a uniform vertical magnetic field B0, as shown in the figure. Initially, it hangs vertically downwards, because of acceleration due to gravity 𝑔, on two conducting supports at P and Q. When a current 𝐼 is passed through the loop, the loop turns about the line PQ by an angle 𝜃 given by
A
tanθ=(mg)πrlB0
B
tanθ=(mg)2πrlB0
C
tanθ=(2mg)πrlB0
D
tanθ=(πrlB0)mg
Answer
tanθ=(mg)πrlB0
Explanation
Solution
The correct option is (A):tanθ=(mg)πrlB0