Advertisements
Advertisements
Question
Given a uniform electric filed \[\vec{E} = 4 \times {10}^3 \ \hat{i} N/C\]. Find the flux of this field through a square of 5 cm on a side whose plane is parallel to the Y-Z plane. What would be the flux through the same square if the plane makes a 30° angle with the x-axis?
Advertisements
Solution
When the plane is parallel to the y-z plane:
\[\text { Electric flux }, \phi = \vec{E .} A^\rightharpoonup \]
\[\text { Here }: \]
\[ \vec{E} = 4 \times {10}^3 \ \hat{i} N/C\]
\[ A^\rightharpoonup = \left( 5 cm \right)^2 \ \hat{i} = 0 . 25 \times {10}^{- 2} \ \hat{i} m^2 \]
\[ \therefore \phi = \left( 4 \times {10}^3 \ \hat{i} \right) . \left( 25 \times {10}^{- 4} \ \hat{i} \right)\]
\[ \Rightarrow \phi = 10 \text { Weber }\]
When the plane makes a 30° angle with x-axis, the area vector makes a 60° angle with the x-axis.
\[\phi = \vec{E .} \vec{A} \]
\[ \Rightarrow \phi = EA \cos\theta\]
\[ \Rightarrow \phi = \left( 4 \times {10}^3 \right)\left( 25 \times {10}^{- 4} \right)\cos60°\]
\[ \Rightarrow \phi = \frac{10}{2}\]
\[ \Rightarrow \phi = 5 \text { Weber }\]
APPEARS IN
RELATED QUESTIONS
Find out the outward flux to a point charge +q placed at the centre of a cube of side ‘a’. Why is it found to be independent of the size and shape of the surface enclosing it? Explain.
Two charges of magnitudes −2Q and +Q are located at points (a, 0) and (4a, 0) respectively. What is the electric flux due to these charges through a sphere of radius ‘3a’ with its centre at the origin?
Two charges of magnitudes +4Q and − Q are located at points (a, 0) and (− 3a, 0) respectively. What is the electric flux due to these charges through a sphere of radius ‘2a’ with its centre at the origin?
Figure shows three point charges +2q, −q and + 3q. Two charges + 2q and −q are enclosed within a surface ‘S’. What is the electric flux due to this configuration through the surface ‘S’?

A charged particle q is placed at the centre O of cube of length L (A B C D E F G H). Another same charge q is placed at a distance L from O. Then the electric flux through ABCD is ______.
A point charge q is placed at a distance a/2 directly above the centre of a square of side a. The electric flux through the square is ______.
If the electric flux entering and leaving an enclosed surface respectively is Φ1 and Φ2, the electric charge inside the surface will be
In a region of space having a uniform electric field E, a hemispherical bowl of radius r is placed. The electric flux Φ through the bowl is:
The electric charges are distributed in a small volume. The flux of the electric field through a spherical surface of radius 10 cm surrounding the total charge is 20 V-m. The flux over a concentric sphere of radius 20 cm will be ______.
An electric field is given by `(6 hat i + 5 hat j + 3 hat k)` N/C. The electric flux through a surface area `30 hat i` m2 lying in YZ-plane (in SI unit) is ______.
