What happens when a ferromagnetic material is placed in an external magnetic field?a) the domain orientation may changeb) the domain boundaries may changec) new domains are createdd) both the domain orientation and boundaries may change
Earth’s Magnetic area there may be a lot uncertainty about the foundation and nature of the earth’s magnetic area. A simplistic mannequin is that of a gigantic bar magnet with a dipole subject surrounding it (determine 14 – 1). Measurements product of the orientation and strength of the magnetic subject in hundreds of thousands of areas across the earth suggest the bar magnet mannequin, which is roughly spherical and has traces of drive plunging into the polar regions, is a good approximation of the real magnetic subject. The earth’s core is suggestion to be largely made from molten iron, which possibly the source of the discipline. Siesmic stories indicate that the inside core is solid and the outer core is liquid. The inside core is above the Curie temperature, so it can not contribute to the Earth’s magnetic area. Today's theories recommend the magnetic area is triggered by go with the flow of fabric within the outer core which generates a waft of electrical present, which ordinarily additionally contributes to the formation of an electromagnetic discipline.
The answer is d. Further information : Why is a material magnetic? Magnetism arises due to the flow of current. Now electron which is a fundamental charge particle moves in particular orbits (energy states ) around the nucleus (built up of protons and neutron). It moves such due to the minimization of its potential and kinetic energy. There is a constant exchange of photons (quanta of EM field) b/w thei proton and electron which makes possible this motion. Now electron being a charge particle also rotates on its own axis (just like earth does). This is the spin of electron ( in reality spin is abstract property). Analogy with earth helps to visualize. Now this spin is what constitues a small electronic current. Thus electron has a magnetic moment which is known as Bohr Magneton. This magnetic moment interacts with the external magnetic field and rotates in the presence of external field( experiences torque). Now electrons are not isolated. Each electron spin interacts with the other and a spin wave ( quanta is Magnon) flows through the material. Thus the material is a ferromagnetic is there are spontaneous fictitious domains containing a large number of alligned spins in a particular direction. When external magnetic field is applied , both domain orientation and boundary will change .
