Magnetism and Matter Test 32

Result

Magnetism and Matter Test 32

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

A current carrying loop is placed in a uniform magnetic field in four different orientations I, II, III & IV. Arrange them in the decreasing order of potential Energy.

A
$$I > III > II > IV$$

B
$$I > II > III > IV$$

C
$$I > IV > II> III$$

D
$$III> IV > I > II$$

Solution

The potential energy is given by:
$$U=−\vec M.\vec B=−MBcos\theta$$

In case I:
$$\theta=180^o$$
So, $$U=\pm MB$$

In case II:
$$\theta=90^o$$
So, $$U=0$$

In case III:
$$\theta$$ is acute,
So, $$U=−ve$$

In case IV:
$$\theta$$ is obtuse
So, $$U=+ve$$

$$\therefore\ I>IV>II>III$$
Question 2
1 / -0

If a solution of ferromagnetic material is poured into a U-tube and one arm of this is placed between the poles of a strong magnet with the meniscus in line with the field, then the level of the solution will:

A
Rise

B
Fall

C
Rise till the liquid comes out

D
Remain unchanged

Solution
Question 3
1 / -0

................................ was invented by Michel Faraday.

A
Electromagnetic induction

B
Transformer

C
Dynamo

D
B and C

Solution

Electromagnetism was invented by Michel Faraday.
It is defined as the quantity of the electric charge on one mole of electrons. It has value, 1 F = 96500 C/mol.
Question 4
1 / -0

Three plotting compasses are placed close to a current carrying wire wrapped around an insulator as shown in the figure.
How many compass needles will change direction if the current through the wire is increased? (Ignore the effect of the earth's magnetic field.)

A
0

B
1

C
2

D
3
Question 5
1 / -0

In the given figure, the electron enters into the magnetic field. It deflects in x direction .
Two parallel beams of electrons moving in the same direction produce a mutual force

A
+ ve X direction

B
- ve X direction

C
+ ve Y direction

D
- ve Y direction

Solution

The direction of the force on a moving charge depends on the direction of its velocity. The magnetic force acting on a moving charged particle is the cross product of the velocity and the magnetic field
Question 6
1 / -0

Ratio of magnetic intensities for an axial point and a point on broad side- on position at equal distance d from the centre of magnet will be $$or$$ The magnetic field at a distance d from a short bar magnet in longitudinal and transverse positions are in the ratio

A
$$1:1$$

B
$$1:6$$

C
$$2:1$$

D
$$3:2$$

Solution

$$Given:$$ Ratio of magnetic intensities for an axial point and a point on broad side- on position at equal distance $$d$$ from the centre of magnet.
$$Solution:$$ We know that,
$$B_{1}=\frac{2 M}{d^{3}} \cdot B_{2}=\frac{M}{d^{3}} ; \quad \therefore \frac{B_{1}}{B_{2}}=2: 1$$
$$So,the$$ $$correct$$ $$option:C$$
Question 7
1 / -0

For substances hysteresis (B-H) curves are given as shown in figure. For making temporary magnet which of the following is best

A

B

C

D
Question 8
1 / -0

An isolated unit north pole expending force of $$2\times { 10 }^{ -7 }N$$ when kept at a distance 1m from a magnetic pole in air. The strength of thr pole is:

A
$$2\times { 10 }^{ 7 }A-m$$

B
$$2A-m$$

C
$$2\times { 10 }^{ -11 }A-m$$

D
$$4Am$$

Solution

Given: force experienced,$$F=2*10^{-7}N$$
magnetic pole strength of north pole, $$m_1=1A-m$$
distance between north pole and magnetic pole is,$$ r=1m$$
To Find: magnetic pole strength of magnetic pole is,$$m_2=?$$
Solution: as we know,
force experienced, $$F=\dfrac{\mu_o}{4\pi}*\dfrac{m_1*m_2}{r^{2}}$$
$$m_2=F*\dfrac{4\pi}{\mu_o*m_1}*r^{2}$$
$$m_2=\dfrac{2*10^{-7}*10^{7}*1}{1}$$
$$m_2=2A-m$$
Question 9
1 / -0

Which of the following particles will deviate $$(< \pi /2)$$ maximum and when they enter magnetic field region perpendicularly with same velocity and travels same distance:

A
$$Be$$

B
Proton

C
$$\alpha-$$particle

D
$$Li++$$

Solution

Given: Each particle has same magnetic field and same velocity.
Solution: As we know the formula of radius of orbit of moving particle in magnetic field:
$$R=\frac{mv}{qB} $$
Ratio $$ \frac{m}{q} $$ is constant
Whose radius is maximum will have least deflection,
By applying this rule we get to know that ,Li$$^{2+}$$ has minimum value of $$ \frac{m}{q}$$ so maximum value of deflection.
Hence the correct option is D
Question 10
1 / -0

A bar magnet is demagnetized by inserting it inside a solenoid of length $$0.2m, 100turas$$, and carrying a current of $$5.2A$$. The coercivity of the bar magnet is:

A
$$1200\, A/m$$

B
$$2600\, A/m$$

C
$$5200\, A/jm$$

D
$$285\, A/m$$

Solution

Coercivity $$= H = \dfrac{B}{\mu_0}$$
$$ni = \dfrac{N}{\ell}i = \dfrac{100}{0.2}\times 5.2$$
$$=2600 A/m$$