Question
Write an expression for intensity of magnetisation field at a point located at a distance $r$ on its axis due to a small bar magnet having magnetic moment $\overrightarrow{ m }$.

Answer

$\vec{B}=\frac{\mu_0}{4 \pi} \times \frac{2 \vec{m}}{r^3}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

A uniform wire of resistance $50\Omega$ is cut into 5 equal parts. These parts are now connected in parallel. What is the value of equivalent resistance of the combination?
A straight horizontal conducting rod of length 0.45 m and mass 60 g is suspended by two vertical wires at its ends. A current of 5.0 A is set up in the rod through the wires.
  1. What magnetic field should be set up normal to the conductor in order that the tension in the wires is zero?
  2. What will be the total tension in the wires if the direction of current is reversed keeping the magnetic field same as before? (Ignore the mass of the wires.) g = 9.8 m s–2.
A particle executes simple harmonic motion. Let P be a point near the mean position and Q be a point near an extreme. The speed of the particle at P is larger than the speed at Q. Still the particle crosses P and Q equal number of times in a given time interval. Does it make you unhappy?
The charging current for a capacitor is 0.25 A. What is the displacement current across its plates?
Answer the following questions, which help you understand the difference between Thomson’s model and Rutherford’s model better.

Keeping other factors fixed, it is found experimentally that for small thickness t, the number of α-particles scattered at moderate angles is proportional to t. What clue does this linear dependence on t provide?

Which part of electromagnetic spectrum is used in satellite communication?
Define the activity of a given radioactive substance. Write its S.I. unit.
You are given following three lenses. Which two lenses will you use as an eyepiece and as an objective to construct an astronomical telescope?
Lenses Power (P) Aperture (A)
L1 3 D  8 cm
L2 6 D 1 cm
L3 10 D 1 cm
The storage battery of a car has an emf of 12 V. If the internal resistance of the battery is 0.4 $\Omega$, what is the maximum current that can be drawn from the battery?
How much is the diameter of hydrogen atom?