CBSE Questions for Class 12 Medical Physics Magnetism And Matter Quiz 1 - MCQExams.com

The force which a magnet exerts on iron and steel is called the.
  • electric force
  • magnetic force
  • nuclear force
  • gravitational force
Magnetic lines of force due to a bar magnet do not intersect because 
  • A point always has a single net magnetic field
  • The lines have similar charges and so repel each other
  • The lines always diverge from a single point
  • None of these
Relative permittivity and permeability of a material are $$\epsilon_{\mathrm{r}}$$ and $$\mu_{\mathrm{r}}$$, respectively. Which of the following values of these quantifies are allowed for a diamagnetic material? 
  • $$\epsilon_{\mathrm{r}}=0.5,\ \mu_{\mathrm{r}}=0.5$$
  • $$\epsilon_{\mathrm{r}}=1.5,\ \mu_{\mathrm{r}}=1.5$$
  • $$\epsilon_{\mathrm{r}}=0.5,\ \mu_{\mathrm{r}}=1.5$$
  • $$\epsilon_{\mathrm{r}}=1.5,\ \mu_{\mathrm{r}}=0.5$$
The B-H curve for a ferromagnet is shown in the figure. The ferromagnet is placed inside a ling solenoid with $$1000$$ turns/cm.. The current that should be passed in the solenoid to demagnetise the ferromagnet completely is:
868212_dacb31dcc4e64b6abb3b755d2b261c6e.png
  • $$2 mA$$
  • $$1 mA$$
  • $$3 mA$$
  • None of these
Curie temperature is the temperature above which
  • a ferromagnetic material becomes paramagnetic
  • a paramagnetic material becomes diamagnetic
  • a ferromagnetic material becomes diamagnetic
  • a paramagnetic material becomes ferromagnetic.
An example of a perfect diamagnet is a superconductor. This implies that when a superconductor is put in a magnetic field of intensity $$B$$, the magnetic field $$B_S$$ inside the superconductor will be such that :
  • $$B_S=-B$$
  • $$B_S=0$$
  • $$B_S=B$$
  • $$B_S < B$$ but $$B_S\neq 0$$
Three identical bars A, B and C are made of different magnetic materials. When kept in a uniform magnetic field, the field lines around them look as given in the figure . Make the correspondence of these bars with their material being diamagnetic (D), ferromagnetic (F) and paramagnetic (P) .
99262.png
  • $$A \leftrightarrow F, B \leftrightarrow D, C \leftrightarrow P$$
  • $$A \leftrightarrow D, B \leftrightarrow P, C \leftrightarrow F$$
  • $$A \leftrightarrow F, B \leftrightarrow P, C \leftrightarrow D$$
  • $$A \leftrightarrow P, B \leftrightarrow F, C \leftrightarrow D$$
Needles $$N_{1}, N_{2}$$ and $$N_{3}$$ are made of a ferromagnetic, a paramagnetic and a diamagnetic substance respectively. A magnet when brought close to them will 
  • attract all three of them.
  • attract $$\mathrm{N}_{1}$$ and $$\mathrm{N}_{2}$$ strongly but repel $$\mathrm{N}_{3}$$. 
  • attract $$\mathrm{N}_{1}$$ strongly, $$\mathrm{N}_{2}$$ weakly and repel $$\mathrm{N}_{3}$$ weakly.
  • attract $$\mathrm{N}_{1}$$ strongly, but repel $$\mathrm{N}_{2}$$ and $$\mathrm{N}_{3}$$ weakly.
The figure gives experimentally measured B vs. H variation in a ferromagnetic material. The retentivity, co-ercivity and saturation, respectively, of the material are :
1697157_bb522d10aa5244b1a21184908cf2ab0b.png
  • $$1.5 T, 50 A/m $$ and $$1.0T$$
  • $$150 A/m, 1.0 T$$ and $$1.5 T$$
  • $$1.5 T, 50 A/m$$ and $$1.0 T$$
  • $$1.0 T, 50 A/m$$ and $$1.5 T$$
A thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence the rod gains gravitational potential energy. The work required to do this comes from.
  • The lattice structure of the material of the rod
  • The current source
  • The induced electric field due to the changing magnetic field
  • The magnetic field
  • Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
  • Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
  • Assertion is correct but Reason is incorrect.
  • Both Assertion and Reason are incorrect.
The variation of magnetic susceptibility with the temperature of a ferromagnetic material can be plotted as?
A paramagnetic material is kept in a magnetic field. The field is increased till the magnetization becomes constant. If the temperature is now decreased, the magnetization :
  • will decrease
  • will increase
  • remain constant
  • may increase or decrease
The permanent magnetic moment of the atoms of a material is not zero. The material  :
  •  must be paramagnetic
  • must be diamagnetic
  • must be ferromagnetic
  • may be paramagnetic
Choose the correct alternative, in relation to properties of magnetic lines of force.
  • Magnetic lines of force start from south pole and end on north pole
  • Magnetic lines of force intersect each other at the poles
  • Magnetic lines of force are far from each other where the field is strong
  • Tangent at any point on the magnetic lines of force gives the direction of the magnetic field at that point.
A bar magnet placed in non-uniform magnetic field experiences.
  • Only torque
  • Only force
  • Both torque and force
  • Neither force not torque
The magnetic intensities at points lying at the same distance from the magnetic pole are:
  • same both in magnitude and direction.
  • same in magnitude and different in direction.
  • different in magnitude but same in direction.
  • different both in magnitude and direction.

Which of the following is/are diamagnetic?
  • Bismuth
  • Antimony
  • Water
  • Chromium

Magnetic lines of force are:
  • continuous
  • discontinuous
  • some times continuous and some times discontinuous
  • nothing can be said

In case of a bar magnet, lines of magnetic induction
  • start from the north pole and end at the south pole
  • run continuously through the bar magnet and outside
  • emerge in circular paths from the middle of the bar
  • are produced only at the north pole like rays of light from a bulb

Out of dia, para and ferromagnetism, the universal property of all substances is
  • diamagnetism
  • paramagnetism
  • ferromagnetism
  • antiferromagnetism
Assertion (A) : To protect any instrument from external magnetic field, it is put inside an iron box
Reason (R) : Iron is a ferromagnetic substance
  • Both A and R are true and R is the correct explanation of A
  • Both A and R are true and R is not correct explanation of A
  • A is true, but R is false
  • A is false, but R is true
A paramagnet magnet behaves like a solenoid because both contain currents in the form of
  • Circles
  • Parabola
  • Straight line
  • Ellipse

Magnetic lines of force
  • can intersect
  • are open loops
  • are real
  • are closed loops

Ferromagnetic ore properties are due to
  • filled inner sub-shells
  • vacant inner sub-shells
  • partially filled inner sub-shells
  • all the sub-shells equally filled

Permanent magnets are made from
  • diamagnetic substances
  • paramagnetic substance
  • ferromagnetic substances
  • wood

The relative permeability of a material is $$0.9$$. The material is
  • diamagnetic
  • para magnetic
  • ferro magnetic
  • non-magnetic

Liquids and gases never exhibit
  • diamagnetic properties
  • para magnetic properties
  • ferro magnetic properties
  • electro magnetic properties

A material produces a magnetic field which oppose the applied magnetic field, then it is
  • diamagnetic
  • para magnetic
  • electro magnetic
  • ferro magnetic

Copper is __________.
  • diamagnetic
  • paramagnetic
  • ferromagnetic
  • antiferromagnetic
A compass needle, which shows the direction at the earth's magnetic pole is
  • Vertical
  • No particular direction
  • Bent at 45$$^{0}$$ to the vertical
  • Horizontal
The relative permeability of silicon is $$0.99837$$ and that of palladium is $$1.00692$$, choose the correct option from the following :
  • silicon is paramagnetic and palladium is ferromagnetic
  • silicon is ferromagnetic and palladium is paramagnetic
  • silicon is diamagnetic and palladium is paramagnetic
  • Both are paramagnetic

The relative permeability is represented by$$\mu _{r}$$ and susceptibility is denoted by $$\chi $$ for a magnetic substance then for a paramagnetic substance.
  • $$\mu _{r} < 1,\chi < 0$$
  • $$\mu _{r} < 1,\chi > 0$$
  • $$\mu _{r} > 1,\chi < 0$$
  • $$\mu _{r} > 1,\chi > 0$$

A material produces a magnetic field which helps the applied magnetic field, then it is
  • diamagnetic
  • paramagnetic
  • electro magnetic
  • ferro magnetic

The susceptibility of a diamagnetic substance is
  • $$\infty $$
  • zero
  • small but negative
  • small but positive

Alnico is used for making permanent magnets because it has
  • High coercivity and high retentivity
  • high coercivity and low retentivity
  • low coercivity and low retentivity
  • low coercivity and high retentivity

Domain formation is the necessary feature of
  • ferro magnetism
  • paramagnetism
  • diamagnetism
  • electro magnetism

Susceptibility is large and positive for
  • para magnetic
  • diamagnetic
  • ferro magnetic
  • electromagnetic

The magnetic force required to demagnetise the material is
  • retentivity
  • coercivity
  • energy loss
  • hysterisis
Assertion(A) : Earth's magnetic field inside a closed iron box is less as compared to the outside.
Reason(R) : The magnetic permeability of iron is low.
  • Both A, R are true and R is the correct explanation of A
  • Both A, R are true and R is not correct explanation of A
  • A is true R is false
  • A is false R is true

The hysteresis cycle curve for the material of a permanent magnet is :
  • short and wide
  • tall and narrow
  • tall and wide
  • short and narrow

Susceptibility is small and positive for
  • para magnetic only
  • diamagnetic only
  • ferro magnetic only
  • Both 1 & 3
From the following ,pick a property that is associated to ferromagnetic materials only :
  • attracting magnetic substance
  • hysterisis
  • directional property
  • susceptibility independent of temperature

The substance used for preparing electro magnets is :
  • soft iron
  • steel
  • nickel
  • copper

The curie weiss law is obeyed by iron
  • at all temperatures
  • above the curie temperature
  • below the curie temperature
  • at the curie temperature

The permanent magnetic moment of atoms or molecules of a diamagnetic material is
  • small
  • large
  • negative
  • zero

For which of the following substances, the magnetic susceptibility is independent of temperature :
  • diamagnetic
  • ferromagnetic
  • paramagnetic
  • diamagnetic and ferromagnetic
Ferromagnetism is not found in
  • conductors
  • semiconductors
  • Cobalt
  • gases

Ferromagnetic materials have their properties due to
  • vacant inner subshells
  • partially filled inner subshells
  • filled inner subshells
  • completely filled outer shells
Hysteresis is shown by which of the following materials
  • paramagnetic only
  • ferromagnetic only
  • diamagnetic only
  • both B and C
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