How Does Magnetic Field Orientation Affect Torque on a Solenoid?

[jcvince17]

Torque on a soleniod / coil in magnetic field

Homework Statement

A solenoid having 180 turns and a cross-sectional area of 6.68 cm² carries a current of 1.12 A

1) If it is placed in a uniform 1.12 T magnetic field, find the torque this field exerts on the solenoid if its axis is oriented perpendicular to the field.

2) If it is placed in a uniform 1.12 T magnetic field, find the torque this field exerts on the solenoid if its axis is oriented at 45.0* with the field

Homework Equations

τ = IBAsinθ

The Attempt at a Solution

1) know the following:
N=180 , B = 1.12T , I = 1.12A , θ = 90* , area = .0668 m2

τ = IBAsinθ

τ = (1.12 A) (1.12 T) ( .0668 m2) (sin90) = 0.084
I then take that and multiply by number of turns = 0.084 x 180 = 15.08

But my answer is wrong. where am I going wrong?



2) N=180 , B = 1.12T , I = 1.12A , θ = 45* , area = .0668 m2

τ = IBAsinθ

τ = (1.12 A) (1.12 T) ( .0668 m2) (sin45) = 0.060
I then take that and multiply by number of turns = 0.060 x 180 = 10.67

This is also a wrong answer. Where am I going wrong here?


Please help

 

[alphysicist]

Hi jvince17,

Homework Statement

A solenoid having 180 turns and a cross-sectional area of 6.68 cm² carries a current of 1.12 A

1) If it is placed in a uniform 1.12 T magnetic field, find the torque this field exerts on the solenoid if its axis is oriented perpendicular to the field.

2) If it is placed in a uniform 1.12 T magnetic field, find the torque this field exerts on the solenoid if its axis is oriented at 45.0* with the field

Homework Equations

τ = IBAsinθ

The Attempt at a Solution

1) know the following:
N=180 , B = 1.12T , I = 1.12A , θ = 90* , area = .0668 m2

This area is not correct. Remember that the area given in the problem was in cm², not cm. Do you see what it need to be?

 

[jcvince17]

Hi jvince17,



This area is not correct. Remember that the area given in the problem was in cm², not cm. Do you see what it need to be?

I sure do! thank you very much. I changed my area and recalculated and both answers are now correct!

 

[florence.noy]

Good evening,

This is my first time doing this since i had just completed my registration. I am really very eager to know exactly my answer to the problem because when i tried solving it for number 1 my answer is (0) because i am using (cos 90) which is equal to 0. In number 2 my answer is 0.1066522483 N.m. I do not know if I am correct. If I am wrong please I need to know where did I get it wrong.

Thank you very much and more power to us!