MCQ
The magnetic force required to demagnetise the material is:
- ARetentivity.
- BCoercivity.
- CEnergy loss.
- DHysterisis.
✓
Answer
- Coercivity.
Explanation:
Coercivity is the magnetic force required to demagnetise the material.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
In an electroplating experiment, m gm of silver is deposited when 4 ampere of current flows for 2 minute. The amount (in gm) of silver deposited by 6 ampere of current for 40 second will be
|
(a) 4 m |
(b) m/2 |
(c) m/4 |
(d) 2 m |
The relative permittivity $(\in_{r})$ of a medium is :
→Two satellites A and B move round the earth in the same orbit. The mass of B is twice the mass of A:
- Speeds of A and B are equal.
- The potential energy of earth +A is same as that of earth +B.
- The kinetic energy of A and B are equal.
- The total energy of earth +A is same as that of earth +B.
Same current is flowing through two parallel conducting wires at a distance $d$ in opposite directions. The intensity of magnetic field at the midpoint between the wires is :
→A coil of circular cross-section having 1000 turns and 4cm2 face area is placed with its axis parallel to a magnetic field which decreases by 10–2 Wb m–2 in 0.01 s. The e.m.f. induced in the coil is:
The slope of plate characteristic of a vacuum tube diode for certain operating point on the curve is 
The plate resistance of the diode and its nature respectively
|
(a) 100 kilo-ohms static |
(b) 1000 kilo-ohms static |
|
(c) 1000 kilo-ohms dynamic |
(d) 100 kilo-ohms dynamic |
Six charges, three positive and three negative of equal magnitude are to be placed at the vertices of a regular hexagon such that the electric field at O is double the electric field when only one positive charge of same magnitude is placed at R. Which of the following arrangements of charges is possible for P, Q, R, S, T and U respectively
|
(a) +, -, +, -, -, + |
(b) +, -, +, -, +, - |
(c) +, +, -, +, -, - |
(d) -, +, +, -, +, - |
The angle of dip at the magnetic equator is
| (a) 0° | (b) 45° | (c) 30° | (d) 90° |
A rod of legth l rotates with a uniform angular velocity $\omega$ about its perpendicular bisector. A uniform magnetic field B exists parallel to the axis of rotation. The potential difference between the two ends of the rod is:
→The following diagram indicates the energy levels of a certain atom when the system moves from 2E level to E, a photon of wavelength λ is emitted. The wavelength of photon produced during its transition from 
level to E is
|
(a) λ/3 |
(b) 3 λ/4 |
(c) 4 λ/3 |
(d) 3 λ |