Advertisements
Advertisements
प्रश्न
S is the surface of a lump of magnetic material.
- Lines of B are necessarily continuous across S.
- Some lines of B must be discontinuous across S.
- Lines of H are necessarily continuous across S.
- Lines of H cannot all be continuous across S.
विकल्प
a and b
b and c
c and d
a and d
Advertisements
उत्तर
a and d
Explanation:
Here we are introducing the properties of magnetic field lines (B), for any magnet, it forms continuous closed loops. This is unlike the electric dipole where these field lines begin from a positive charge and end on the negative charge or escape to infinity.
Also, magnetic intensity (H) outside any magnet is H = `B/mu_0` and inside the magnet H = `B/(mu_0mu_r)`, where `mu_r` is the relative permeability of material (magnetic).
Magnetic field lines for magnetic field `(vecB)` is continuous upon a transition through the interface.
Also, magnetic intensity `(vecH)` varies for inside and outside the lump. So, lines of `(vecH)` cannot all be continuous across S.
APPEARS IN
संबंधित प्रश्न
Distinguish between diamagnetic and paramagnetic substances.
A meter gauge train is heading north with speed 54 km/hr in earth's magnetic field 3 x 10-4T. The e.m.f. induced across the axle joining the wheels is ..........
(a) 0.45 mV
(b) 4.5 mV
(c) 45 mV
(d) 450 m V
The magnetic susceptibility of annealed iron at saturation is 4224. Find the permeability of
annealed iron at saturation. (μ0 = 4Π × 10−7 SI unit)
The susceptibility of a magnetic material is 0·9853. Identify the type of magnetic material. Draw the modification of the field pattern on keeping a piece of this material in a uniform magnetic field.
Which of the following substances are diamagnetic?
Bi, Al, Na, Cu, Ca and Ni
The relative magnetic permeability of a magnetic material is 800. Identify the nature of magnetic material and state its two properties.
Choose the correct option:
A magnetising field of 360 Am−1 produces a magnetic flux density (B) = 0.6T in a ferromagnetic material. What is its permeability in Tm A−1?
Two identical bar magnets each of magnetic moment M, separated by some distance are kept perpendicular to each other. The magnetic induction at a point at the same distance d from the centre of magnets, is (µ0 = permeability of free space)
All atoms of a magnetic substance have a resultant magnetic moment even in absence of external magnetic field. The substance is ______.
If a magnetic field is applied to a liquid in one arm of a narrow U-tube, the liquid level in that arm is lowered. The liquid in U-tube arm is ______.
Above the curie temperature the susceptibility of ferromagnetic substance varies ____________.
Magnetic field lines are always nearly normal to the surface of a ferromagnet at every point. (This fact is analogous to the static electric field lines being normal to the surface of a conductor at every point.) Why?
Assertion: The ferromagnetic substance do not obey Curie’s law.
Reason: At Curie point a ferromagnetic substance start behaving as a paramagnetic substance.
The coercivity of a small magnet where the ferromagnet gets demagnetized is 3 × 103 Am–1. The current required to be passed in a solenoid of length 10 cm and number of turns 100, so that the magnet gets demagnetized when inside the solenoid, is ______.
A hydrogen atom is paramagnetic. A hydrogen molecule is
Essential difference between electrostatic shielding by a conducting shell and magnetostatic shielding is due to ______.
- electrostatic field lines can end on charges and conductors have free charges.
- lines of B can also end but conductors cannot end them.
- lines of B cannot end on any material and perfect shielding is not possible.
- shells of high permeability materials can be used to divert lines of B from the interior region.
Explain the Domain theory in brief.
Magnetic susceptibility of a diamagnetic substance ______.
