Question:
Magnetic materials used for making permanent magnets (P) and magnets in a transformer (T) have different properties of the following, which property best matches for the type of magnet required?
Magnetic materials used for making permanent magnets (P) and magnets in a transformer (T) have different properties of the following, which property best matches for the type of magnet required?
Show Hint
Permanent magnets need to retain magnetism and resist demagnetisation, so both retentivity and coercivity are large; transformer cores need low hysteresis loss.
Updated On: Nov 5, 2026
- T : Large retentivity, small coercivity
- P : Large retentivity, large coercivity
- P : Small retentivity, large coercivity
- T : Large retentivity, large coercivity
Show Solution
Verified By Collegedunia
The Correct Option is B
Solution and Explanation
A permanent magnet (P) must keep its magnetisation and not be easily demagnetised: large retentivity and large coercivity (wide hysteresis loop, e.g. steel, alnico).
A transformer core (T) is repeatedly magnetised and demagnetised, so it needs a narrow hysteresis loop with small coercivity (and low hysteresis loss), e.g. soft iron.
Option (3) is wrong for P (small retentivity) and option (4) is wrong for T (large coercivity). Option (1) is not the best match, since the key requirement for a permanent magnet is large retentivity with large coercivity. The best matching statement is option (2).
Answer: (2) P : Large retentivity, large coercivity
A transformer core (T) is repeatedly magnetised and demagnetised, so it needs a narrow hysteresis loop with small coercivity (and low hysteresis loss), e.g. soft iron.
Option (3) is wrong for P (small retentivity) and option (4) is wrong for T (large coercivity). Option (1) is not the best match, since the key requirement for a permanent magnet is large retentivity with large coercivity. The best matching statement is option (2).
Answer: (2) P : Large retentivity, large coercivity
Was this answer helpful?
0
0
Top JEE Main Physics Questions
- Two masses $m$ and $\frac{m}{2}$ are connected at the two ends of a massless rigid rod of length $l$. The rod is suspended by a thin wire of torsional constant $k$ at the centre of mass of the rod-mass system(see figure). Because of torsional constant $k$, the restoring torque is $\tau =k\theta$ for angular displacement $\theta$. If the rod is rota ted by $\theta_0$ and released, the tension in it when it passes through its mean position will be:
A black body is at a temperature of 2880 K. The energy of radiation emitted by this body with wavelength between 499 nm and 500 nm is U1, between 999 nm and 1000 nm is U2 and between 1499 nm and 1500 nm is U3. The Wien's constant, b = 2.88×106 nm-K. Then,
- $I _{ CM }$ is the moment of inertia of a circular disc about an axis (CM) passing through its center and perpendicular to the plane of disc $I_{A B}$ is it's moment of inertia about an axis $AB$ perpendicular to plane and parallel to axis $CM$ at a distance $\frac{2}{3} R$ from center Where $R$ is the radius of the dise The ratio of $I _{ AB }$ and $I _{ CM }$ is $x: 9$ The value of $x$ is______
- A nucleus disintegrates into two smaller parts, which have their velocities in the ratio $3: 2$ The ratio of their nuclear sizes will be $\left(\frac{x}{3}\right)^{\frac{1}{3}}$ The value of ' $x$ ' is:-
- A particle starts with an initial velocity of 10.0 m/s along x-direction and accelerates uniformly at the rate of 2.0 m/s$^2$. The time taken by the particle to reach the velocity of 60.0 m/s is
View More Questions
Top JEE Main Magnetism and matter Questions
- The magnetic potential due to a magnetic dipole at a point on its axis situated at a distance of 20 cm from its center is \( 1.5 \times 10^{-5} \, \text{Tm} \). The magnetic moment of the dipole is _______ \( \text{Am}^2 \).
(Given: \( \frac{\mu_0}{4\pi} = 10^{-7} \, \text{TmA}^{-1} \)) - Two long, straight wires carry equal currents in opposite directions as shown in figure. The separation between the wires is 5.0 cm. The magnitude of the magnetic field at a point P midway between the wires is ____ μT
(Given: \(\mu_0 = 4\pi \times 10^{-7} \, \text{TmA}^{-1}\))
- A regular polygon of 6 sides is formed by bending a wire of length 4 \(\pi\) meter. If an electric current of \(4 \pi \sqrt3 \) A is flowing through the sides of the polygon, the magnetic field at the centre of the polygon would be \(x × 10^{–7}\) T. The value of \(x\) is ____.
- An electron moves through a uniform magnetic field \( \vec{B} = B_0 \hat{i} + 2B_0 \hat{j} \, \text{T} \). At a particular instant of time, the velocity of the electron is \( \vec{u} = 3\hat{i} + 5\hat{j} \, \text{m/s} \). If the magnetic force acting on the electron is \( \vec{F} = 5e k \, \text{N} \), where \( e \) is the charge of the electron, then the value of \( B_0 \) is _____ T
- A proton and a deuteron (\( q = +e, \, m = 2.0u \)) having the same kinetic energies enter a region of uniform magnetic field \( \vec{B} \), moving perpendicular to \( \vec{B} \). The ratio of the radius \( r_d \) of the deuteron path to the radius \( r_p \) of the proton path is:
View More Questions
Top JEE Main Questions
- Two masses $m$ and $\frac{m}{2}$ are connected at the two ends of a massless rigid rod of length $l$. The rod is suspended by a thin wire of torsional constant $k$ at the centre of mass of the rod-mass system(see figure). Because of torsional constant $k$, the restoring torque is $\tau =k\theta$ for angular displacement $\theta$. If the rod is rota ted by $\theta_0$ and released, the tension in it when it passes through its mean position will be:
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)- The value of is
- The number of terms of an is even. The sum of the odd terms is and of the even terms is . The last term exceeds the first by . Then the number of terms in the series is ______.
A black body is at a temperature of 2880 K. The energy of radiation emitted by this body with wavelength between 499 nm and 500 nm is U1, between 999 nm and 1000 nm is U2 and between 1499 nm and 1500 nm is U3. The Wien's constant, b = 2.88×106 nm-K. Then,
View More Questions