Question

Ch 27 HW Exercise 27.49 13 of 20 Constants A coil with a magnetic moment of 1.42 A⋅m2 is oriented initially with its magnetic moment antiparallel to a uniform magnetic field of magnitude 0.835 T . Part A What is the change in potential energy of the coil when it is rotated 180 ∘ so that its magnetic moment is parallel to the field? UU = nothing J Request Answer Provide Feedback

Answer 1

Answer:

ΔU = -2.37 J

Explanation:

given,                              

magnetic moment = 1.42 A⋅m²

uniform magnetic field = 0.835 T

Change in potential energy = ?

Potential energy                  

 $U = \vec{\mu}. \vec{B}$

there is scalar product so,      

 $U = \mu Bcos \theta$

when θ = 0°              

 $U_1 =\mu B cos 0^0$

 $U_1 =\mu B$            

when θ = 180°                  

 $U_2 =\mu B cos 180^0$

 $U_2 = -\mu B$              

Change in potential energy

$\Delta U = U_2 - U_1$      

$\Delta U = -\mu B-\mu B$          

$\Delta U = -2 \mu B$                  

$\Delta U = -2\times 1.42 \times 0.835$

ΔU = -2.37 J