A circular loop of radius r , having N turns and carrying current I , is kept in the X Y plane. It is then subjected to a uniform magnetic field B → = B x i ^ + B Y j ^ + B z k ^ Obtain expression for the magnetic potential energy of the coil-magnetic field system.

For the circular loop, m = ± N I π r 2 k ^ Magnetic potential energy, U = m → . B → = ± N I π r 2 k ^ . B x i ^ + B y j ^ + B z k ^ = ± π r 2 N I B z

A long solenoid with air core has n turns per unit length and carries a current I . Using Ampere's circuital law, derive an expression for the magnetic field B → at an interior point on its axis. Write an expression for magnetizing intensity H → in the interior of the solenoid.

The above figure shows the sectional view of a long solenoid. At various turns of the solenoid, current comes out of the plane of paper at points marked ⊙ and enters the plane of paper at points marked ⨂ To determine the magnetic field B → at any inside point, consider a rectangular closed path abcd as the Amperean loop. According to Ampere's circuital law, ∮ B → . d l → = μ 0 × total current through the loop a b c d Now, ∮ B → . d l → = ∫ a b B → . d l → + ∫ b c B → . d l → + ∫ c d B → . d l → + ∫ d a B → . d l → But ∫ b c B → . d l → = ∫ b c B d l cos 90 ° = 0 ∫ c d B → . d l → = 0 [ ∴ B = 0 for outside of solenoid] ∫ d a B → . d l → = ∫ b c B d l cos 90 ° = 0 ∴ ∮ B → . d l → = ∫ a b B → . d l → = ∫ 0 l B d l = B l Where, l = length of the side a b of the rectangular loop a b c d . Let number of turns per unit length of the solenoid = n Then number of turns in length l of the solenoid = n l Thus, the current I of the solenoid threads the loop a b c d , n l times. ∴ Total current threading the loop a b c d , = n l I ∴ B l = μ 0 n l I ⇒ B = μ 0 n I The magnetizing intensity H → in the interior of the solenoid, H → = μ 0 n I .

EASY

12th CBSE

IMPORTANT

Earn 100

Out of the following, identify the materials which can be classified as diamagnetic:
1.Bismuth

2. Aluminium

3. copper

4. sodium
Write one property to distinguish between paramagnetic and diamagnetic materials.

Important Questions on Magnetism

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 5 - Magnetism>Text Based Exercises>Q 43

Out of the following, identify the materials which can be classified as diamagnetic:
1.Copper

2. Aluminium

3. Bismuth

4. Sodium
Write one property to distinguish between paramagnetic and diamagnetic materials.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 5 - Magnetism>Text Based Exercises>Q 43

Out of the following, identify the materials which can be classified as diamagnetic:
1.Sodium

2.Aluminium

3.Bismuth

4.copper
Write one property to distinguish between paramagnetic and diamagnetic materials.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 5 - Magnetism>Text Based Exercises>Q 44

A uniform magnetic field gets modified as shown below when two specimens $X$ and $Y$ are placed in it. Identify whether specimens $X$ and $Y$ are diamagnetic, paramagnetic or ferromagnetic.

Question Image

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 5 - Magnetism>Text Based Exercises>Q 44

How is the magnetic permeability of specimen $X$ different from that of specimen $Y$ ?

Question Image

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 5 - Magnetism>Text Based Exercises>Q 1

Write the expression for the equivalent magnetic moment of a planer current loop of area

A

, having

N

turns and carrying a current

i

. Use the expression to find the magnetic dipole moment of a revolving electron.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 5 - Magnetism>Text Based Exercises>Q 1

A circular loop of radius

r

, having

N

turns and carrying current

I

, is kept in the

X Y

plane. It is then subjected to a uniform magnetic field

\vec{B} = B_{x} \hat{i} + B_{Y} \hat{j} + B_{z} \hat{k}

Obtain expression for the magnetic potential energy of the coil-magnetic field system.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 5 - Magnetism>Text Based Exercises>Q 2

A long solenoid with air core has n turns per unit length and carries a current

I

. Using Ampere's circuital law, derive an expression for the magnetic field

\vec{B}

at an interior point on its axis. Write an expression for magnetizing intensity

\vec{H}

in the interior of the solenoid.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 5 - Magnetism>Text Based Exercises>Q 2

A (small) bar of material, having magnetic susceptibility

x

, is now put along the axis and near the centre, of the solenoid which is carrying

a d . c .

current through its coils. After some time, the bar is taken out and suspended freely with an unspun thread. Will the bar orient itself in magnetic meridian if (a)

x < 0

(b)

x > 1000

Out of the following, identify the materials which can be classified as diamagnetic: 1.Bismuth 2. Aluminium 3. copper 4. sodium Write one property to distinguish between paramagnetic and diamagnetic materials.

Important Questions on Magnetism

Learn and Prepare for any exam you want !

Out of the following, identify the materials which can be classified as diamagnetic:
1.Bismuth

2. Aluminium

3. copper

4. sodium
Write one property to distinguish between paramagnetic and diamagnetic materials.