Magnetism and Matter · Physics · COMEDK
MCQ (Single Correct Answer)
On both sides of a magnetic needle, two short magnets A and B are placed on the same horizontal line which is perpendicular to the magnetic meridian. The south poles of $A$ and $B$ are facing each other, which are 10 cm and 20 cm respectively from the magnetic needle. If the needle remains undeflected, the ratio of the magnetic moment of $A$ to that $B$ is:
The material selected for making a permanent magnet should have:
Paramagnetic substances
A. Move from a region of strong magnetic field to weak magnetic field
B. Has susceptibility less than zero
C. Attract strongly towards external magnetic field
D. Align themselves along the directions of external magnetic field
A bar magnet of length 12 cm is placed such that its north pole points towards the geographic north. Two neutral points which are separated by 16 cm are obtained on the equatorial axis of the bar magnet. What is the pole strength of the bar magnet if the horizontal component of the earth's field is $1.25 \times 10^{-5} \mathrm{~T}$ ?
A bar magnet is held perpendicular to a uniform field. If the couple acting on the magnet is to be halved, by rotating it, the angle by which it is to be rotated is
For a paramagnetic material, the dependence of the magnetic susceptibility $$\chi$$ on the absolute temperature is given as
The magnetic susceptibility of an ideal diamagnetic substance is
The percentage increase in magnetic field $$\mathrm{B}$$ when the space within a current carrying solenoid is filled with a medium of susceptibility 0.004 is
Steel is preferred to soft iron for making permanent magnets because,
If $$\theta_1$$ and $$\theta_2$$ be the apparent angles of dip observed in two vertical planes at right angles to each other, then the true angle of $$\operatorname{dip} \theta$$ is given by
The magnetic permeability '$$\mu$$' a of a paramagnetic substance is :
Find the pole strength of a magnet of length $$2 \mathrm{~cm}$$, if the magnetic field strength $B$ at distance $$10 \mathrm{~cm}$$ from the centre of a magnet on the axial line of the magnet is $$10^{-4} \mathrm{~T}$$.
A bar magnet of length $$6 \mathrm{~cm}$$, is placed in the magnetic meridian with $$N$$ pole, pointing towards the geographical north. Two neutral points, separated by a distance of $$8 \mathrm{~cm}$$ are obtained on the equitorial axis of the magnet. If $$B_H=1.2 \times 10^{-5} \mathrm{~T}$$. Then the pole strength of the magnet is
A bar magnet is oscillating in the earth's magnetic field with a period T. What happens to its period and motion, if its mass is quadrupled?
The relative permeability of iron is 6000. Its magnetic susceptibility is
The intensity of magnetic field due to an isolated pole of strength $$m_p$$ at a point distant $$r$$ from it will be
The angle which the total magnetic field of earth makes with the surface of the earth is called
The angle of dip of at a place where horizontal and vertical components of earth’s magnetic field are equal is