Math Problem Statement

There is an electric flux of 39.5 N·m²/C through the square region shown in the figure. Each side of the square has a length of 0.100 m, n̂ is the unit vector normal to the plane of the surface, and the electric field is at an angle of θ = 145.0° relative to the plane of the surface. Assuming that the field is uniform over the region shown, what is the magnitude E of the electric field?

Solution

The problem involves calculating the magnitude EE of the electric field given the electric flux ΦE=39.5Nm2/C\Phi_E = 39.5 \, \text{N} \cdot \text{m}^2 / \text{C}, the area of the square, and the angle θ=145\theta = 145^\circ between the electric field and the normal vector n^\hat{n}.

The electric flux is related to the electric field by the equation:

ΦE=EAcos(θ)\Phi_E = E A \cos(\theta)

where:

  • ΦE\Phi_E is the electric flux.
  • EE is the magnitude of the electric field.
  • AA is the area of the square.
  • θ\theta is the angle between the electric field and the normal to the surface.

Given:

  • ΦE=39.5Nm2/C\Phi_E = 39.5 \, \text{N} \cdot \text{m}^2 / \text{C}
  • A=(0.100m)2=0.0100m2A = (0.100 \, \text{m})^2 = 0.0100 \, \text{m}^2
  • θ=145\theta = 145^\circ

Rearranging the equation to solve for EE:

E=ΦEAcos(θ)E = \frac{\Phi_E}{A \cos(\theta)}

Substituting the known values:

E=39.50.0100cos(145)E = \frac{39.5}{0.0100 \cdot \cos(145^\circ)}

Now, calculating the value of cos(145)\cos(145^\circ):

cos(145)=cos(35)0.8192\cos(145^\circ) = -\cos(35^\circ) \approx -0.8192

Thus:

E=39.50.0100(0.8192)E = \frac{39.5}{0.0100 \cdot (-0.8192)}

Let's calculate EE. math

Given values

flux = 39.5 # N·m^2/C side_length = 0.100 # m theta_deg = 145 # degrees

Calculate the area of the square

area = side_length ** 2

Calculate the cosine of the angle

theta_rad = math.radians(theta_deg) cos_theta = math.cos(theta_rad)

Calculate the electric field magnitude E

E = flux / (area * cos_theta) EThe calculated magnitude of the electric field is approximately 4822N/C4822 \, \text{N/C}. The negative sign indicates that the direction of the electric field is opposite to the direction of the normal vector. Since we are looking for the magnitude, we take the absolute value:

E=4822N/CE = 4822 \, \text{N/C}

Would you like further clarification or more questions on this topic? Here are some related questions you might find useful:

  1. What is the concept of electric flux and how is it related to the electric field?
  2. How does the angle θ\theta affect the electric flux through a surface?
  3. Can electric field magnitude be determined without knowing the angle?
  4. How do different surface orientations affect the calculation of electric flux?
  5. What other scenarios could you calculate electric flux for using different geometries?

Tip: Always double-check the angle's reference direction to ensure correct sign when calculating flux.

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Math Problem Analysis

Mathematical Concepts

Electric Flux
Electric Field
Vector Components
Trigonometry

Formulas

Electric flux formula: Φ_E = E * A * cos(θ)
Area of a square: A = side²

Theorems

Gauss's Law for Electric Flux

Suitable Grade Level

Undergraduate (Physics - Electromagnetism)