Question:
Four very long wires are arranged as shown, so that their cross-section forms a square, with connections at the ends so that current I flows through all four wires as shown. Length of each side of the formed such square is b. The magnetic field at the central point P (centre of the square) is
Four very long wires are arranged as shown, so that their cross-section forms a square, with connections at the ends so that current I flows through all four wires as shown. Length of each side of the formed such square is b. The magnetic field at the central point P (centre of the square) is
Updated On: Jul 14, 2022
- $\frac{\mu_0 I}{\pi b} $
- $\frac{2 \mu_0 I}{\pi b} $
- 0
- $\frac{\mu_0 I}{ \sqrt{2} \pi b} $
Hide Solution
Verified By Collegedunia
The Correct Option is C
Solution and Explanation
Since, the current through two wires are from left to right, the magnetic field is directed outwards the plane of the paper.
Also, current through the other two wires are from right to left, the magnetic field due to them is directed inwards the plane of the paper. Since, the value of current
through all the wires is same and point $P$ is equidistant from all the wires, the magnitude of magnetic fields are same. Hence, they are cancelled. So, the net magnetic field is zero.
Was this answer helpful?
0
0
Top Questions on Magnetic Field
- Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A : The potential (V) at any axial point, at 2 m distance(r) from the centre of the dipole of dipole moment vector \(\vec{P}\) of magnitude, 4 × 10-6 C m, is ± 9 × 103 V.
(Take \(\frac{1}{4\pi\epsilon_0}=9\times10^9\) SI units)
Reason R : \(V=±\frac{2P}{4\pi \epsilon_0r^2}\), where r is the distance of any axial point, situated at 2 m from the centre of the dipole.
In the light of the above statements, choose the correct answer from the options given below :- NEET (UG) - 2024
- Physics
- Magnetic Field
- In a uniform magnetic field of \(0.049 T\), a magnetic needle performs \(20\) complete oscillations in \(5\) seconds as shown. The moment of inertia of the needle is \(9.8 \times 10 kg m^2\). If the magnitude of magnetic moment of the needle is \(x \times 10^{-5} Am^2\); then the value of '\(x\)' is
- NEET (UG) - 2024
- Physics
- Magnetic Field
- A tightly wound \(100\) turns coil of radius \(10 cm\) carries a current of \( 7 A\). The magnitude of the magnetic field at the centre of the coil is (Take permeability of free space as \(4\pi×10^{-7}\) SI units):
- NEET (UG) - 2024
- Physics
- Magnetic Field
- An iron bar of length L has magnetic moment M. It is bent at the middle of its length such that the two arms make an angle 60° with each other. The magnetic moment of this new magnet is :
- NEET (UG) - 2024
- Physics
- Magnetic Field
- A sheet is placed on a horizontal surface in front of a strong magnetic pole. A force is needed to :
A. hold the sheet there if it is magnetic.
B. hold the sheet there if it is non-magnetic.
C. move the sheet away from the pole with uniform velocity if it is conducting.
D. move the sheet away from the pole with uniform velocity if it is both, non-conducting and non-polar.
Choose the correct statement(s) from the options given below :- NEET (UG) - 2024
- Physics
- Magnetic Field
View More Questions
Questions Asked in UPSEE exam
- A carnot engine takes 300 calories of heat at 500 K and rejects 150 calories of heat to the sink. The temperature of the sink is
- UPSEE - 2019
- Heat Transfer
- Which of the following is not permissible arrangement of electrons in an atom.
- UPSEE - 2019
- Quantum Mechanical Model of Atom
- If det $\begin{bmatrix}1&1&2\\ 2&4&9\\ t&t^{2}&1+t^{3}\end{bmatrix} = 0 $ , then the values of t are
- UPSEE - 2019
- Properties of Determinants
- The imaginary part of $\left( \frac{1}{2} + \frac{1}{2}i\right)^{10} $ is
- UPSEE - 2019
- Complex Numbers and Quadratic Equations
- Let S be the set of all right angled triangles with integer sides forming consecutive terms of an arithmetic progression. The number of triangles in S with perimeter less than 30 is
- UPSEE - 2019
- Arithmetic Progression
View More Questions
Concepts Used:
Magnetic Field
The magnetic field is a field created by moving electric charges. It is a force field that exerts a force on materials such as iron when they are placed in its vicinity. Magnetic fields do not require a medium to propagate; they can even propagate in a vacuum. Magnetic field also referred to as a vector field, describes the magnetic influence on moving electric charges, magnetic materials, and electric currents.
A magnetic field can be presented in two ways.
- Magnetic Field Vector: The magnetic field is described mathematically as a vector field. This vector field can be plotted directly as a set of many vectors drawn on a grid. Each vector points in the direction that a compass would point and has length dependent on the strength of the magnetic force.
- Magnetic Field Lines: An alternative way to represent the information contained within a vector field is with the use of field lines. Here we dispense with the grid pattern and connect the vectors with smooth lines.
Properties of Magnetic Field Lines
- Magnetic field lines never cross each other
- The density of the field lines indicates the strength of the field
- Magnetic field lines always make closed-loops
- Magnetic field lines always emerge or start from the north pole and terminate at the south pole.