A ferromagnetic material is heated above its curie temperature. Which one is a correct statement
| (a) Ferromagnetic domains are perfectly arranged |
| (b) Ferromagnetic domains becomes random |
| (c) Ferromagnetic domains are not influenced |
| (d) Ferromagnetic material changes itself into diamagnetic material |
(b) Ferromagnetic domains becomes random
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Optical fibres are related with
|
(a) Communication |
(b) Light |
(c) Computer |
(d) None of these |
Conditions of diffraction is
|
(a) |
(b) |
(c) |
(d) None of these |
The number of turns of primary and secondary coils of a transformer are 5 and 10 respectively and the mutual inductance of the transformer is 25 henry. Now the number of turns in the primary and secondary of the transformer are made 10 and 5 respectively. The mutual inductance of the transformer in henry will be
|
(a) 6.25 |
(b) 12.5 |
(c) 25 |
(d) 50 |
A PN- junction has a thickness of the order of
| (a) 1 cm | (b) 1 mm |
(c) 
|
(d) 
|
When phosphorus and antimony are mixed in zermaniun, then
|
(a) P-type semiconductor is formed |
(b) N-type semiconductor is formed |
|
(c) Both (a) and (b) |
(d) None of these |
Which of the following statement is true
|
(a) The presence of a large magnetic flux through a coil maintains a current in the coil if the circuit is continuous |
|
(b) A coil of a metal wire kept stationary in a non-uniform magnetic field has an e.m.f. induced in it |
|
(c) A charged particle enters a region of uniform magnetic field at an angle of 85° to the magnetic lines of force;the path of the particle is a circle |
|
(d) There is no change in the energy of a charged particle moving in a magnetic field although a magnetic force is acting on it |
