iCON Education - Magnetism and Matter AP-EAPCET Test

Question 1: Palette 1/21

AP-EAPCET 2025 MCQ

If the given figure shows the relation between magnetic field ( $B$-along $Y$-axis) and magnetic intensity ( $H$-along $X$-axis) of a ferromagnetic material, then the point that represents coercivity of the material is

AP EAPCET 2025 - 27th May Morning Shift Physics - Magnetism and Matter Question 1 English

$P$

$Q$

$R$

$S$

Question 2: Palette 2/21

AP-EAPCET 2025 MCQ

A sample of a ferromagnetic iron in the shape of a cube of side $1.0 \mu \mathrm{~m}$ contains $8.7 \times 10^{28}$ atoms per cubic metre and the magnetic dipole moment of each iron atom is $93 \times 10^{-24} \mathrm{Am}^2$. Then, the maximum possible magnetic dipole moment (in $\mathrm{Am}^2$ ) of the sample is nearly

$8.1 \times 10^{-12}$

$8.1 \times 10^{-14}$

$81 \times 10^{-14}$

$81 \times 10^{-16}$

Question 3: Palette 3/21

AP-EAPCET 2025 MCQ

A sample of paramagnetic salt contains $2 \times 10^{24}$ atomic dipoles each of dipole moment $15 \times 10^{-23} \mathrm{JT}^{-1}$. The sample is placed under homogeneous magnetic field of 0.6 T and cooled to a temperature 4.2 K . The degree of magnetic saturation achived is $20 \%$. Then total dipole moment of the sample for a magnetic field of 0.9 T and a temperature of 2.8 K is

$4.5 \mathrm{JT}^{-1}$

$13.5 \mathrm{JT}^{-1}$

$0.64 \mathrm{JT}^{-1}$

$7 \mathrm{JT}^{-1}$

Question 4: Palette 4/21

AP-EAPCET 2025 MCQ

The work done in rotating a bar magnet which is initially in the direction of a uniform magnetic field through $45^{\circ}$ is $W$. The additional work to be done to rotate the magnet further through $15^{\circ}$ is

$\frac{W}{\sqrt{2}}$

$\frac{W}{2}$

$W \sqrt{2}$

2 W

Question 5: Palette 5/21

AP-EAPCET 2025 MCQ

Materials suitable for permanent magnets should have

Iow retentivity and 'ow coercivity

Iow retentivity ar nigh coercivity

high retentivity and low coercivity

high retentivity and high coercivity

Question 6: Palette 6/21

AP-EAPCET 2025 MCQ

A short bar magnet of magnetic moment $10^4 \mathrm{JT}^{-1}$ is free to rotate in a horizontal plane. The work done in rotating the magnet slowly from the direction parallel to a horizontal magnetic field of $4 \times 10^{-5} \mathrm{~T}$ to a direction $60^{\circ}$ to the direction of the field is

0.2 J

2.6 J

0.4 J

6.2 J

Question 7: Palette 7/21

AP-EAPCET 2025 MCQ

A short bar magnet has a magnetic moment of $0.48 \mathrm{JT}^{-1}$. The magnitude of magnetic field at a point at 10 cm distance from the centre of the magnet on its axis is

0.96 gauss

0.48 gauss

1.92 gauss

1.44 gauss

Question 8: Palette 8/21

AP-EAPCET 2025 MCQ

A short bar magnet is placed in a uniform magnetic field of 2 T such that the axis of the magnet makes an angle of $45^{\circ}$ with the direction of the magnetic field. If the torque acting on the magnet is $0.36 \sqrt{2} \mathrm{~N}-\mathrm{m}$, then the moment of the magnet is

$0.54 \mathrm{JT}^{-1}$

$0.18 \mathrm{JT}^{-1}$

$0.72 \mathrm{JT}^{-1}$

$0.36 \mathrm{JT}^{-1}$

Question 9: Palette 9/21

AP-EAPCET 2024 MCQ

The relation between $\mu$ and $H$ for a specimen of iron is $\mu=\left[\frac{1.4}{H}+12 \times 10^{-4}\right] \mathrm{Hm}^{-1}$. The value of $H$ which produces flux density of 1 T will be ( $\mu=$ magnetic permeability, $H=$ magnetic intensity)

$250 \mathrm{Am}^{-1}$

$500 \mathrm{Am}^{-1}$

$750 \mathrm{Am}^{-1}$

$10^3 \mathrm{Am}^{-1}$

Question 10: Palette 10/21

AP-EAPCET 2024 MCQ

At a place the horizontal component of earth's magnetic field $3 \times 10^{-5} \mathrm{~T}$ and the magnetic declination is $30^{\circ}$. A compass needle of magnetic moment $18 \mathrm{Am}^2$ pointing towards geographic north at this place experiences a torque of

$36 \times 10^{-5} \mathrm{Nm}$

$18 \times 10^{-5} \mathrm{Nm}$

$54 \times 10^{-5} \mathrm{Nm}$

$27 \times 10^{-5} \mathrm{Nm}$

Question 11: Palette 11/21

AP-EAPCET 2024 MCQ

If the vertical component of the earth's magnetic field is 0.45 G at a location and angle of dip is $60^{\circ}$, then magnetic field of earth in that location is

0.26 G

0.52 G

0.3 G

0.7 G

Question 12: Palette 12/21

AP-EAPCET 2024 MCQ

At a place where the magnitude of the earth's magnetic field is $4 \times 10^{-5} \mathrm{~T}$, a short bar magnet is placed with its axis perpendicular to the earth's magnetic field direction. If the resultant magnetic field at a point at a distance of 40 cm from the centre of the magnet on the normal bisector of the magnet is inclined at $45^{\circ}$ with the earth's field, then the magnele moment of the magnet is

$38.4 \mathrm{Am}^2$

$51.2 \mathrm{Am}^2$

$12.8 \mathrm{Am}^2$

$25.6 \mathrm{Am}^3$

Question 13: Palette 13/21

AP-EAPCET 2024 MCQ

Any magnetic material loses its magnetic property when it is

dipped in water

dipped in sand

attached to an iron piece

heated to high temperature

Question 14: Palette 14/21

AP-EAPCET 2024 MCQ

The domain in ferromagnetic material is in the form of a cube of side $2 \mu \mathrm{~m}$. Number of atoms in that domain is $9 \times 10^{10}$ and each atom has a dipole movement of $9 \times 10^{-24} \mathrm{Am}^2$. The magnetisation of the domain is (approximately).

$10 \times 10^4 \mathrm{Am}^{-1}$

$8 \times 10^4 \mathrm{Am}^{-1}$

$12 \times 10^4 \mathrm{Am}^{-1}$

$9 \times 10^4 \mathrm{Am}^{-1}$

Question 15: Palette 15/21

AP-EAPCET 2024 MCQ

A magnet suspended in a uniform magnetic field is heated, so as to reduce its magnetic moment by $19 \%$. By doing this, the time period of the magnet approximately

incresse by $11 \%$

decrease by $19 \%$

increases by $19 \%$

decreases by $4 \%$

Question 16: Palette 16/21

AP-EAPCET 2022 MCQ

Two short magnets of equal dipole moments $M$ are fastened perpendicularly at their centres. The magnitude of the magnetic field at a distance $d$ from the centre on the bisector of the right angle is ($\mu_0=$ Permeability of free space)

$\frac{\mu_0}{4 \pi} \frac{2 \sqrt{2} M}{d^3}$

$\frac{\mu_0}{4 \pi} \frac{5 M}{d^3}$

$\frac{\mu_0}{4 \pi} \frac{2 M}{d^3}$

$\frac{\mu_0}{4 \pi} \frac{10 M}{d^3}$

Question 17: Palette 17/21

AP-EAPCET 2022 MCQ

A steel wire of length $l$ and magnetic moment $M$ is bent into a semicircular arc of radius $R$. The new magnetic moment is

$M$

$\frac{2 R M}{\pi l}$

$\frac{2 M}{\pi}$

$\frac{2 \pi R M}{1}$

Question 18: Palette 18/21

AP-EAPCET 2022 MCQ

A magnetic needle free to rotate in a vertical plane parallel to the magnetic meridian has its north tip pointing down at $30^{\circ}$ with the horizontal. The horizontal component of the earth's magnetic field at the place is 0.3 G . Then the magnitude of the earth's magnetic field at the location is

$\frac{\sqrt{3}}{5} G$

$\sqrt{3} \mathrm{G}$

$\frac{20}{\sqrt{3}} \mathrm{G}$

$\frac{2}{\sqrt{3}} \mathrm{G}$

Question 19: Palette 19/21

AP-EAPCET 2022 MCQ

A compass needle oscillates 20 times per minute at a place where the dip is $45^{\circ}$ and the magnetic field is $B_1$. The same needle oscillates 30 times per minute at a place where the dip is $30^{\circ}$ and magnetic field is $B_2$. Then, $B_1: B_2$ is

$9 \sqrt{3}: 4 \sqrt{2}$

$4 \sqrt{2}: 9 \sqrt{3}$

$3 \sqrt{3}: 2 \sqrt{2}$

$2 \sqrt{2}: 3 \sqrt{3}$

Question 20: Palette 20/21

AP-EAPCET 2021 MCQ

A paramagnetic sample showing a net magnetisation of $0.8 \mathrm{~A} \mathrm{~m}^{-1}$, when placed in an external magnetic field of strength $0.8 \mathrm{~T}$, at a temperature $5 \mathrm{~K}$. If the temperature is raised to $20 \mathrm{~K}$, then the magnetisation becomes

$0.8 \mathrm{~A} \mathrm{~m}^{-1}$

$0.2 \mathrm{~A} \mathrm{~m}^{-1}$

$0.1 \mathrm{~A} \mathrm{~m}^{-1}$

$0.4 \mathrm{~A} \mathrm{~m}^{-1}$

Question 21: Palette 21/21

AP-EAPCET 2021 MCQ

The plane of a dip circle is set in the geographic meridian and the apparent dip is $\delta_1$. It is then set in a vertical plane perpendicular to the geographic meridian. The apparent dip angle is $\delta_2$. The declination $\theta$ at the place is

$\tan ^{-1}\left(\tan _1 \tan _2\right)$

$\tan ^{-1}\left(\tan \delta_1+\tan \delta_2\right)$

$\tan ^{-1}\left(\frac{\tan \delta_1}{\tan \delta_2}\right)$

$\tan ^{-1}\left(\tan \delta_1-\tan \delta_2\right)$