physics MCQs - 12th class Chapter 06 Mcqs

1

Which type of solid is characterized by a regular arrangement of molecules constant throughout the crystal?

A

Amorphous solids

B

Glassy solids

C

Crystalline solids

D

Polymeric solids

2

What is the smallest three-dimensional basic structure that repeats itself to form a crystal lattice?

A

Molecule

B

Atom

C

Lattice

D

Unit cell

3

The ability of a body to return to its original shape after the removal of an external force is called?

A

Plasticity

B

Deformation

C

Stress

D

Elasticity

4

What is the SI unit of stress?

A

Joule

B

Newton

C

Watt

D

Pascal

5

The fractional change in length is known as?

A

Tensile stress

B

Shear strain

C

Volumetric strain

D

Tensile strain

6

The ratio of stress to strain is constant for a given material, provided the force is not too great. This ratio is called?

A

Young's Modulus

B

Bulk Modulus

C

Modulus of Elasticity

D

Shear Modulus

7

Which of the following is an example of a ductile substance?

A

Glass

B

High carbon steel

C

Copper

D

Concrete

8

The greatest stress a material can endure without losing straight-line proportionality between stress and strain is called?

A

Elastic limit

B

Yield point

C

Proportional limit

D

Ultimate tensile strength

9

The energy stored in a deformed material can be calculated from the area under which graph?

A

Force-time graph

B

Velocity-time graph

C

Stress-time graph

D

Force-extension graph

10

In energy band theory, the band occupying the valence electrons is known as?

A

Conduction band

B

Forbidden band

C

Valence band

D

Energy gap

11

Materials with a large energy gap between the valence and conduction bands are typically?

A

Conductors

B

Insulators

C

Semiconductors

D

Superconductors

12

In which materials do the valence and conduction bands largely overlap?

A

Insulators

B

Semiconductors

C

Conductors

D

Polymers

13

At 0 K, a pure silicon (Si) crystal behaves as a?

A

Perfect conductor

B

Superconductor

C

Perfect insulator

D

Semiconductor

14

The process of adding a small amount of impurity into a pure semi-conductor lattice is called?

A

Annealing

B

Doping

C

Sintering

D

Hardening

15

When a silicon crystal is doped with a pentavalent element like phosphorus, what type of semiconductor is formed?

A

p-type

B

n-type

C

intrinsic

D

extrinsic-p

16

In a p-type semiconductor, the majority charge carriers are?

A

Electrons

B

Protons

C

Neutrons

D

Holes

17

A vacancy of an electron in the valence band of a semiconductor is known as a?

A

Hole

B

Proton

C

Positron

D

Donor ion

18

Materials whose resistivity becomes zero below a certain critical temperature (Tc) are called?

A

Perfect conductors

B

Superconductors

C

Ideal insulators

D

Ferromagnets

19

The first superconductor was discovered in 1911 by observing which element?

A

Lead

B

Tin

C

Aluminum

D

Mercury

20

A superconductor with a critical temperature above 77 K is referred to as a?

A

Low temperature superconductor

B

Type-II superconductor

C

High temperature superconductor

D

Ceramic superconductor

21

The magnetic properties of materials originate from?

A

Nuclear spin only

B

Electron orbital motion only

C

Electron spin only

D

Electron spin and orbital motion

22

Substances with atoms that have a resultant magnetic field and behave like tiny magnets are called?

A

Diamagnetic

B

Paramagnetic

C

Ferromagnetic

D

Antiferromagnetic

23

In which substances do the magnetic fields from electron orbital and spin motions add up to zero?

A

Paramagnetic

B

Ferromagnetic

C

Diamagnetic

D

All solids

24

Iron, Cobalt, and Nickel are examples of which type of magnetic material?

A

Diamagnetic

B

Paramagnetic

C

Ferromagnetic

D

Non-magnetic

25

What are the small regions of macroscopic size in a ferromagnetic substance called?

A

Grains

B

Crystals

C

Domains

D

Lattices

26

The temperature at which a ferromagnetic material becomes paramagnetic is known as?

A

Boiling point

B

Melting point

C

Critical temperature

D

Curie temperature

27

Which material is considered a 'soft' magnetic material?

A

Steel

B

Alnico V

C

Iron

D

Chromium dioxide

28

The phenomenon where the magnetism of a material lags behind the magnetizing current is called?

A

Retentivity

B

Coercivity

C

Hysteresis

D

Saturation

29

The value of magnetization remaining in a material when the magnetizing current is reduced to zero is called?

A

Coercivity

B

Saturation

C

Hysteresis

D

Retentivity

30

What does the area of a hysteresis loop represent?

A

Energy dissipated as heat

B

Magnetic saturation

C

Coercive force

D

Retentivity

31

Which type of solids have a disordered structure similar to liquids?

A

Crystalline

B

Polymeric

C

Amorphous

D

Ionic

32

Plastics and synthetic rubbers are examples of what type of solids?

A

Crystalline

B

Ionic

C

Metallic

D

Polymeric

33

The force applied on a unit area to produce a change in shape, volume, or length is defined as?

A

Strain

B

Elasticity

C

Stress

D

Pressure

34

What is strain a measure of?

A

Force applied

B

Original length

C

Deformation of a solid

D

Cross-sectional area

35

The modulus of elasticity that relates to a change in volume is called?

A

Young's Modulus

B

Shear Modulus

C

Bulk Modulus

D

Tensile Modulus

36

Substances that break just after the elastic limit is reached are known as?

A

Ductile

B

Brittle

C

Malleable

D

Soft

37

In the equation Work done = 1/2 * F₁ * l₁, what does F₁ represent?

A

Final strain

B

Original length

C

Stretching force

D

Young's modulus

38

What is the charge of a hole in a semiconductor?

A

Negative

B

Neutral

C

Positive

D

Variable

39

A trivalent impurity like aluminum added to silicon creates what kind of semiconductor?

A

n-type

B

intrinsic

C

p-type

D

g-type

40

An impurity atom that readily donates a free electron is called a(n)?

A

Acceptor atom

B

Donor atom

C

Valence atom

D

Core atom

41

The modulus of elasticity has the same units as?

A

Strain

B

Force

C

Length

D

Stress

42

Natural rubber is composed entirely of a hydrocarbon with the formula?

A

(C₅H₈)ₙ

B

(C₂H₄)ₙ

C

(CH₂)ₙ

D

(C₆H₁₂)ₙ

43

What is the Curie temperature for iron?

A

100 °C

B

450 °C

C

750 °C

D

1000 °C

44

A material suitable for making a permanent magnet should have?

A

Low retentivity, low coercivity

B

High retentivity, low coercivity

C

Low retentivity, high coercivity

D

High retentivity, high coercivity

45

The energy gap for a semiconductor is typically of the order of?

A

1 eV

B

5 eV

C

10 eV

D

0.1 eV

46

In an unstretched state, the magnetic domains in a ferromagnetic material are oriented?

A

In parallel

B

In an orderly fashion

C

In a disorderly fashion

D

Perpendicular to each other

47

What does UTS stand for in the context of material properties?

A

Ultimate Tensile Strain

B

Ultimate Tensile Stress

C

Uniform Tensile Strength

D

Ultimate Torsion System

48

The maximum stress a material can withstand is its?

A

Proportional limit

B

Elastic limit

C

Yield strength

D

Ultimate tensile strength

49

When a body is subjected to an external force, it is said to be in a state of?

A

Rest

B

Motion

C

Stress

D

Equilibrium