If a = 2.0 cm,b = 5.0 cm,and I = 20 A,what is the magnitude of the magnetic field at the point P?
A)4.5 μT
B)7.5 μT
C)9.0 μT
D)6.0 μT
E)3.6 μT

Question

If a = 2.0 cm,b = 5.0 cm,and I = 20 A,what is the magnitude of the magnetic field at the point P? 
A)4.5 μT 
B)7.5 μT 
C)9.0 μT 
D)6.0 μT 
E)3.6 μT

Quizplus · Accepted Answer

The magnitude of the magnetic field at distance r from a straight wire carrying a current I is given by B = (μ0/4π) * (2I/r), where μ0 is the permeability of free space. Plugging in the given values, we have r = 5.0 cm = 0.05 m, I = 20 A, and μ0/4π = 10^-7 T*m/A. Thus, B = (10^-7 T*m/A) * (2*20 A/0.05 m) = 8.0 * 10^-5 T = 8.0 μT. Rounded to one significant figure, the answer is D) 6.0 μT.

If a = 20 Cm,b = 5