How to Calculate Flux through a Square Plate at an Inclined Angle

[marisa29]

Homework Statement

The flux through a square plate, area 1 m^2, inclined at at an angle of 30 degrees to a field of strength of 100 N/C is

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Homework Equations

Flux=EACos(degree)

The Attempt at a Solution

= (100 N/C) (1m^2) Cos (60)
95 Nm^2/C (not one of the options)

 

[LowlyPion]

Cos 30 = .866

 

[marisa29]

Cos 30 = .866

Cos 30 = .866

O.k so i wouldn't do the angle perpendicular? So i put in cos (30)

30 \
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sorry don't know if the 30 degrees being there matters. When i put in the cos (30) i didn't get that ( does my calculator need to be in degrees ? ) O.k Thanx for any help. Also once i put the 100 N/C * 1m^2* Cos(30) i get 86.6 which is one of the options . Thank you

 

[LowlyPion]

Degrees, not radians.

You can always figure the correct values for 30 degrees and 45.

A 45 degree angle means the sides are equal and hence sin or cos by Pythagoras of 45 is √2/2

For 30 degrees, sin 30 is 1/2 (the side opposite is 1/2 the hypotenuse) and hence the cos 30 must be √3/2.