Physics Magnetism and Matter

Abhishek and Deepak have two samples of magnetic materials X and Y. Experimentally they determine the following properties of the samples.
| | Retentivity | Coercivity |
| :--- | :--- | :--- |
| X | 1.5 T | 20 Am?¹ |
| Y | 1.0 T | 100 Am?¹ |
Considering this, choose best choice

0 Follower 2 Views

Contributor-Level 10

For permanent magnetic Y is good choice, As it has very high coercivity (comparitively)

0 0

New answer posted

a month ago

Which of the following statements are correct?
(A) Electric monopoles do not exist whereas magnetic monopoles exist.
(B) Magnetic field lines due to a solenoid at its ends and outside can not be completely straight and confined.
(C) Magnetic field lines are completely confined within a toroid.
(D) Magnetic field lines inside bar magnet are not parallel.
(E) χ = -1 is the condition for a perfect diamagnetic material, where χ is its magnetic susceptibility.

Choose the correct answer from the options given below:

0 Follower 1 View

Contributor-Level 10

Concept involved: Electric and magnetic field lines
Topic: Magnetics and Magnetic Material
Difficulty level: Moderate
Point of Error: Fact

0 0

New answer posted

a month ago

Four identical long solenoids A, B, C and D are connected to each other as shown in the figure. If the magnetic field at the centre of A is 3T, the field at the centre of C would be: (Assume that the magnetic field is confined within the volume of respective solenoid).

0 Follower 1 View

Raj Pandey

Contributor-Level 9

Magnetic field at centre of a solenoid is proportional to the current through it. Current through C will be one-third of the current through A. So
Magnetic field at the centre of C = 3/3 = 1T.

0 0

New answer posted

a month ago

A square loop of side 2a, and carrying current I, is kept in XZ plane with its centre at origin. A long wire carrying the same current I is placed parallel to the z axis and passing through the point (0, b, 0), (b >> a). The magnitude of the torque on the loop about z - axis is given by:

0 Follower 1 View

Contributor-Level 10

0 0

New answer posted

a month ago

A paramagnetic sample shows a net magnetisation of 6 A/m when it is placed in an external magnetic field of 0.4 T at a temperature of 4 K. When the sample is placed in an external magnetic field of 0.3 T at a temperature of 24 K, then the magnetisation will be :

0 Follower 2 Views

Contributor-Level 10

From aerie's law x = c/r
I = xH
I? = x? H?
I? = x? H?
I? /I? = x? H? /x? H?
I? /I? = T? H? /T? H? = (4 x 0.3)/ (24 x 0.4) = 1/8
I? = T? /8 = 6/8 = 0.75

0 0

New answer posted

a month ago

A small bar magnet placed with its axis at 30° with an external field of 0.06 T experiences a torque of 0.018Nm. The minimum work required to rotate it from its stable to unstable equilibrium position is:

0 Follower 2 Views

Contributor-Level 10

τ? = μ? * B?
⇒ 0.018 = μ(0.06)(sin 30°)
⇒ μ = 0.6
⇒ Work = Uf – Ui
⇒ 2μB
⇒ 7.2 * 10?² J.

0 0

New answer posted

a month ago

A small bar magnet placed with its axis at $30^{?}$ $^{}$ with an external field of $0.06 T$ experiences a torque of $0.018 N m$ . The minimum work required to rotate it from its stable to unstable equilibrium position is:

0 Follower 2 Views

Contributor-Level 10

$\overset{?}{τ} = \overset{?}{μ} * \overset{?}{B}$

$\begin{array}{l} \Rightarrow & 0.018 = μ (0.06) (s i n ? 30^{?}) \\ \Rightarrow & μ = 0.6 \\ \Rightarrow & Work = U_{f} - U_{i} \\ \Rightarrow & 2 μ B \\ \Rightarrow & 7.2 * 10^{- 2} J . \end{array}$

0 0

New answer posted

a month ago

. Given a charge , current and permeability of vacuum . Which of the following quantity has the dimension of momentum ?

0 Follower 2 Views

Contributor-Level 10

Dimension of charge: q = [AT]
Dimension of current I = [A]
Dimension of permeability μ? = [MLT? ²A? ²]
Dimension of momentum: [MLT? ¹]
Let P = q? μ? I? = [AT]? [MLT? ²A? ²]? [A]?
MLT? ¹ = M? L? T? ²? A? ²?
Comparing powers:
y = 1
x - 2y = -1 ⇒ x - 2 (1) = -1 ⇒ x = 1
x - 2y + z = 0 ⇒ 1 - 2 (1) + z = 0 ⇒ z = 1
Hence, the quantity is q¹μ? ¹I¹, or qμ? I.

0 0

New answer posted

a month ago

When the temperature of metal wire is increased from 0°C to 10°C, its length increases by 0.02%. The percentage change in its mass density will be close to:

0 Follower 7 Views