A bar magnet 20 cm in length is placed with its south pole...

A bar magnet $20 \mathrm{~cm}$ in length is placed with its south pole towards geographie north. 'The neutral points are situated at a distance of $40 \mathrm{~cm}$ from centre of the magnet. If horizontal component of earth's field $3.2 \times 10^{-5} \mathrm{~T}$, then pole strength of magnet is (a) $5 \mathrm{Am}$ (b) $10 \mathrm{Am}$ (c) $45 \mathrm{Am}$ (d) 20 Am

A bar magnet $20 \mathrm{~cm}$ in length is placed with its south pole towards geographie north. 'The neutral points are situated at a distance of $40 \mathrm{~cm}$ from centre of the magnet. If horizontal component of earth's field $3.2 \times 10^{-5} \mathrm{~T}$, then pole strength of magnet is
(a) $5 \mathrm{Am}$
(b) $10 \mathrm{Am}$
(c) $45 \mathrm{Am}$
(d) 20 Am

Key Concepts

Magnetic Dipole

A magnetic dipole is a system of two equal and opposite magnetic poles separated by a distance, whose field at large distances resembles that of a simple bar magnet. The magnetic dipole model is fundamental in understanding the spatial variation of the magnetic field produced by magnets and current loops.

Magnetic Field of a Dipole

The magnetic field produced by a dipole decreases with the cube of the distance from the source. This inverse-cube dependence is central to calculations of the field at various points around a magnet, especially in regions where its field is influenced by other external magnetic fields.

Neutral Point

A neutral point in a magnetic field is a location where the net magnetic field is zero due to the cancellation of contributions from different sources. In problems involving both a magnet and an external field, the condition for a neutral point is used to relate the strengths and distances involved.

Earth's Magnetic Field

Earth’s magnetic field, which has a horizontal component, is the natural magnetic field surrounding the Earth that affects compasses and magnetized objects. In many practical and theoretical problems, its known value is used as a reference to determine properties like the pole strength of a magnet.

Pole Strength

Pole strength is a measure of the strength of a magnetic pole, analogous to electric charge in electrostatics, and represents the source of the magnetic field for a magnet. This concept is essential when quantifying how much influence a magnet exerts at a distance, particularly when combined with the magnetic dipole field formulas.

Transcript

Please give Ace some feedback