Matter Interview Questions & Answers

Question 1. How Is A Chemical Change Different Than A Physical Change?

Answer :

During a chemical change the chemical identity of the substance is changed. During a physical change the chemical identity remains the same but the state of matter or physical property has changed (such as water changing to ice).

Question 2. Which Technique Is Used To Separate The Substances From A Mixture?

Answer :

Chromatography is one of the most important techniques for the separation of a mixture by passing it in solution or suspension through a medium in which the components move at different rates. Mixtures that are suitable for separation by chromatography include inks, dyes and colouring agents in food.

Question 3. Explain How Archimedes Proved The King's Crown Was Not Solid Gold?

Answer :

Archimedes realized that when an object is submerged in water its volume is equal to the volume of the displaced water. By dividing the mass of object (such as the crown) by its volume, the object's density can be determined. Archimedes compared the density of the crown to that of solid gold and determined that the crown was not solid gold.

Question 4. In What Way Iodine Can Be Separated From A Mixture Of Potassium Chloride And Iodine?

Answer :

Sublimation is a chemical process where solid is converted into a gas without going through a liquid stage. At standard, atmospheric pressure, a few solids which will sublime are iodine, carbon dioxide, naphthalene and arsenic.

Question 5. Explain The Difference Between A Heterogeneous And Homogeneous Mixture?

Answer :

Heterogeneous is a sample of matter consisting of more than one phase. Homogeneous is a sample of matter consisting of a single phase.

Question 6. What Is Boron?

Answer :

Some elements show the properties between metals and non-metals and are known as metalloids such as boron, silicon etc.

Question 7. What Causes Matter To Change States?

Answer :

The temperature determines the state of a substance. When heated enough, a solid changes to a liquid, and a liquid to a gas. These changes of state take places because the molecules, or tiny bits of matter than make up the substance, vibrate faster when the substance is heated (kinetic energy increases). When the molecules vibrate faster, the attractive forces that hold the molecules together are broken. When cooled (this is the process of losing heat), a gas changes to a liquid, and a liquid changes to a solid.

Question 8. What Is An Element?

Answer :

An element is a substance made up of just one type of atom. Gold is an element. A solid piece of gold is made only of gold atoms. There are 117 known elements and they are all listed on the periodic table.

Question 9. A Mixture Of Salt And Sugar Is Known As?

Answer :

A mixture in which its components do not mix with each other and the distribution of components in different parts of the mixture is not uniform is called heterogeneous mixture.

Question 10. What Are The Four States Of Matter In Order Of Distance Between Particles?

Answer :

Solid, Liquid, Gas, and Plasma.

Question 11. By Which Process Can Sea Water Be Purified?

Answer :

Distillation is a procedure by which two liquids with different boiling points can be separated or it is a process in which the components of a substance or liquid mixture are separated by heating it to a certain temperature and condensing the resulting vapours.

Question 12. What Are The Properties Of Plasma?

Answer :

The particles in plasma are most similar to those in a gas. The particles are negatively charged free electrons and positively charged ions of an atom. The particles are very far apart and the electrons are fast and freely moving.

Question 13. What Are The Properties Of A Liquid?

Answer :

The particles in a liquid are close together but not as close together as in a solid. There is some order to the particles and they flow together freely.

Question 14. Due To Which Process Dry Raisins When Kept In Water Swell Up?

Answer :

A process by which molecules of a solvent tend to pass through a semi-permeable membrane from a less concentrated solution into a more concentrated one is known as osmosis.

Question 15. What Are The Properties Of A Solid?

Answer :

The particles in a solid are closely packed together. They are often in an ordered arrangement called a crystal lattice.

Question 16. What Are The Properties Of A Gas?

Answer :

The particles in gases are not in contact with each other and are free to move relative to one another. The spacing between individual particles is very far apart. A gas has no fixed volume or shape. It occupies both the shape and the volume of the container it occupies.

Question 17. Boyle's Law Relates To Which State Of Matter?

Answer :

Boyle's law, the pressure of certain quantities of gas on stable heat is inversely proportional to its volume.

Question 18. Which Is The Metal That Cannot Be Penetrated By X - Ray?

Answer :

Lead.

Question 19. What Is Means?

Answer :

Elementary particles that are thought to be responsible for the exchange forces between nucleons in a nucleus. Their masses are more than that of electrons and less than that of nucleons.

Question 20. What Is Metrology?

Answer :

The branch of science dealing the accurate measurement of the three fundamental quanlities: mass, length and time. It is generally extended to mean the systematic study of weights and measurements.

Question 21. What Is Zero Point Energy?

Answer :

This refers to the energy possessed by the atoms of molecules of a substance at 0 0 K. It cannot be explained on the basis of classical physics but can be accounted for as a quantum effect.

Question 22. Which Substance Has The Highest Elasticity?

Answer :

Steel.

Question 23. What Is Energy In A Stretched Wire?

Answer :

Half of stress * strain

Question 24. What Is Called The Breaking Stress For A Wire Of Unit Cross Section?

Answer :

Tensile strength.

Question 25. What Are Defined As Young Are Modules?

Answer :

The ratio of linear strain to the normal stress.

Question 26. What Are The Materials Which Lost All Electrical Resistance At Very Low Temperature Called?

Answer :

Super conductors.

Question 27. What Is A Gas Law?

Answer :

It the temperature is constant the pressure of gas is inversely proportional to the volume (the gas will contract if the pressure is raised): PV = RT is the perfect gas equation.

Question 28. What Is Boyle’s Law?

Answer :

It states that at any given temperature, the volume of a given mass of agas is inversely proportional to the pressure applied to it.

Question 29. Who Predicated Gas Law?

Answer :

Robert Boyle, 1662

Question 30. What Is A Capillary?

Answer :

A tube with a narrow and uniform bore is called a capillary. The word “Capilla” in Latin means “Hair”.

Question 31. Why Are Small Drops Of Liquid And Bubbles Spherical?

Answer :

We know that a liquid air interface costs energy, so that for a given volume, the most stable surface is one which has the least surface area, which is a sphere. Thus, if gravity and other forces (like air resistance) are neglected, liquids drops and bubbles would be spherical.

Question 32. What Is Angle Of Contact?

Answer :

It is defined as the angle between the tangent to the liquid surface, at the point of contact and the solid surface inside the liquid. The angle of contact depends upon the nature of solid and liquid i.e. it is different for different pairs of solid and liquids. The angle of contact may be zero, acute or obtuse. The angle of contact is not altered by a change in inclination of the solid surface.

Question 33. What Is A Surface Film?

Answer :

Consider liquid in a board container. Draw a plane at a distance equal to molecular range from the free surface of the liquid and parallel to it. The liquid enclosed between this plane and the free surface of the liquid is called surface film.

Question 34. A Spinning Cricket Ball In Air Does Not Follow A Parabolic Trajectory. Why?

Answer :

A body flows a parabolic path only if it is given a linear velocity, i.e, it is thrown along a straight path, from a certain height.

Question 35. What Is Matter?

Answer :

The planet in the universe, living things such as insects, non living things such as rocks, the air we breathe are all made up of tiny particles called atom which are themselves made up of even smaller particles, called sub atomic particles.

Question 36. What Is Solid?

Answer :

A solid is that state of matter in which its atoms and molecules are strongly bound, so as to preserve their shape and volume. This arrangement of atoms is called solid.

Question 37. What Are The Three States Of Matter?

Answer :

• Solid
• Liquid
• Gas

Question 38. How Many Types Of Solids Are There?

Answer :

There are two type’s solids; crystalline solids and glassy solids (or amorphous solid).

Question 39. What Is Meant By A Crystalline Solid Or A Crystal?

Answer :

In a crystal, the atoms are arranged regularly according to a characteristic geometrical pattern, i.e. there is a long range order in the arrangement of the atoms.

Question 40. How Can You Say That Atoms In A Crystal Are Arranged To A Characteristic Manner?

Answer :

The faces of naturally occurring and artificially grown crystals are flat e.g., sugar, salt, alum, etc., There are definite angles between the faces. Relative areas of the faces have fixed ratios. Due to this, a crystal has a well defined external shape.

Question 41. Name Some Method To Study The Arrangement Of Atoms In A Crystal?

Answer :

• Scanning tunneling
• Electron microscopy
• X - Ray diffraction spectroscopy

Question 42. Why Are Metallic Solids Always Opaque?

Answer :

Because the incident light is readily absorbed by the free electrons in a metal.

Question 43. What Is An Anisotopic Substance?

Answer :

A substance which has different properties in different directions is called an anisotropic substance.

Question 44. What Is Meant By A Glassy Solid Or Amorphous Solid?

Answer :

A solid in which, the atoms are not arranged regularly according to a characteristic geometrical pattern, i.e, there is no long range order in the arrangement of atoms, is called a glassy solid.
Example: Glass, bone, wood, etc.

Question 45. What Does The Large Value Of Young’s Modulus For A Material Represent?

Answer :

It means that the wire requires a very large force to produce a small change in length.

Question 46. What Is Thermal Stress?

Answer :

When a body is heated, but not allowed to expand due to certain constraints, then internal forces are developed which give raise to stress known as thermal stress.

Question 47. What Is Stress?

Answer :

When a force applied on a body, there will be a relative displacement of particles and due to the property of elasticity the particles tend to gain their original position. Stress is defined as the as thermal stress.

Question 48. What Is Normal Stress?

Answer :

Restoring force pursuit area perpendicular to the surface is called normal stress. Its unit is N/m².

Question 49. What Is The Unit Of Stress?

Answer :

In C.G.S system parallel to the surface per unit area is called tangential stress.

Question 50. What Is Tangential Stress?

Answer :

Restoring force parallel to the surface per unit area is called tangential stress.

Question 51. What Is Strain?

Answer :

The ratio of the change in shape to the original shape is called strain. There are three types of strains,

• Longitudinal
• Shearing
• Volume

Question 52. What Is Longitudinal Strain?

Answer :

The ratio of changing in length to original length.

Question 53. Define Shearing Strain?

Answer :

Shearing strain is defined as the angle of shear measured in radians.

Question 54. What Is Volume Strain?

Answer :

The ratio of change in volume to original volume is called volume strain.

Question 55. What Is The Stress - Strain Relation For Rubber?

Answer :

Rubber can be pulled to several times its length and still it returns to its original shape. There is no well defined plastic flow region. Rubber just breaks when deforming forces are removed.

Question 56. What Is Elasticity?

Answer :

Elasticity is that property of a material by virtue of which it tries to regain its original shape and size when deforming forces are removed.

Question 57. The Elastic Property Of A Material Indirectly Related To What?

Answer :

The internal force within the material.

Question 58. Who First Proposed The Idea That “moving Particles Have Wave Characteristics”?

Answer :

Louis de Broglie.

Question 59. How Is An N - Type Semi - Conductor Formed?

Answer :

When germanium crystal is doped with an impurity containing five valence electrons such as arsenic.

Question 60. What Is Plasticity?

Answer :

The region beyond the elastic limit is called plastic region. Ductility and malleability are two important terms which define the behaviour of material in this region. Ductility is related to the elongation of wire beyond yield point while malleability is related to the compression of wire beyond yield point of compression (crushing point).

Question 61. What Is Ductility?

Answer :

A material is said to be ductile if it can be readily drawn into wires. In terms of stress - strain curve materials show ductility behaviour when they are extended beyond yield limit. It is the property related to elongation when the material becomes plastic.

Question 62. What Is Malleability?

Answer :

A material is said to be malleable if it can be readily be beaten out in the form of thin sheets. Malleable material should be soft. It should have large elongation for small stress. In terms of stress - strain graph materials show malleability when they are compressed beyond crushing point, the crushing point is the yield point for compression.

Question 63. What Is Brittleness?

Answer :

Most of the materials first pass through elastic region and then through plastic region before the rapture. However, there is a category of materials known as brittle materials which break even before entering the plastic region.

Question 64. What Is Fluid?

Answer :

A substance which can flow is called a fluid. Liquids and gasses do not have a definite shape. This is because outside forces which tend to change the shape but not the volume of a liquid or gas make it flow. Hence liquids and gases are called fluids.

Question 65. Why Is The Free Surface Of A Small Amount Of Liquid (at Rest Under Gravity) In A Container Is Horizontal?

Answer :

In this case, the force acting is that of gravity, whose direction is the vertical. To be in equilibrium then, the liquid surface has to be perpendicular to the force acting on it, i.e, and horizontal.

Question 66. Define Pressure: It Is Scalar Or Vector? What Is Its S.i Unit?

Answer :

The force acting, per unit area to a surface is called pressure, (pressure is equal to force divided by area). Since the directions of the force acting on a fluid completely described by its magnitude only. So pressure is a scalar quantity. S.I unit of pressure is N / m s or pascal (Pa).

Question 67. What Is The Principle Of A Hydraulic Lift?

Answer :

It is based on Pascal’s law. A hydraulic lift is a device used to support or lift heavy objects.

Question 68. What Is Principle Of Hydraulic Brakes And Hydraulic Transmission?

Answer :

Fluids are ideal for transmitting pressure. We know that the pressure difference between two points in a fluid is either zero. So if the pressure at some point in a fluid is changed, there will be an equal change in pressure at any other point. Thus fluids are ideal for transmitting pressure. This fact is used in a number of devices such as hydraulic brakes and hydraulic transmission.

Question 69. Why A Nail Of Iron Sinks In Water Whereas, A Large Ship Also Made Of Iron Floats?

Answer :

In case of a nail the buoyant (the upward) force is less than the downward force due to weight of the nail. In case of a ship, the buoyant force is greater than the weight of the ship. Buoyant force is the upward thrust of a fluid.

Question 70. Which Factors Are Related To Pressure?

Answer :

Depth, density and gravity, i.e. P = hdg.

Question 71. Who First Measured The Atmospheric Pressure?

Answer :

Evangelista Torricelli in about 1644.

Question 72. What Is Pascal’s Law?

Answer :

Pascal’s law states that if pressure is applied at any point in an enclosed fluid at rest, it is transmitted equally at all points of the liquid.

Question 73. What Is Buoyancy?

Answer :

The upward push applied by the fluid on a submerged object is known as buoyant force and this effect is called buoyancy.

Question 74. What Do You Mean By The Term “viscosity Of A Liquid”?

Answer :

It is ability of a liquid to flow through pipes. Different liquids possess different viscosities, e.g, viscosity of honey is more than that of water.

Question 75. Do Gases Also Possess Viscosity?

Answer :

Yes, but viscosity of gases is much smaller (about hundred times less) than that of a liquid.

Question 76. What Is The Essential Condition So That A Liquid Is Able To Flow Through A Pipe?

Answer :

To make any liquid flow through a pipe, a certain pressure difference must exist between the two ends of the pipe, since a liquid always flows from a region of higher pressure to a region of lower pressure.

Question 77. What Is “rate Of Flow” Of A Liquid Through A Pipe?

Answer :

It is the volume of the liquid flowing per unit time.

Question 78. What Is Steady Flow?

Answer :

A flow is said to be steady if the fluid velocity at a point does not change with time and that it is so for all the points. In a steady flow, a particle always follows a path along which it's predecessor particle went and along which its successor particle also will go.

Question 79. What Is Turbulent Flow?

Answer :

If the flow of a fluid is such that at any point, fluid particles keep on coming and going with different random velocities, the flow is termed as turbulent flow.

Question 80. What Is A Stream Line?

Answer :

In a steady flow, a stream line is the actual path of flow of fluid particle. The pattern of stream lines in a steady flow does not change with time. A stream line may be straight or curved depending upon the pressure on the fluid from the sides.

Question 81. How Will You Find Whether The Flow Of A Liquid Through A Pipe Is Steady Or Turbulent?

Answer :

This can be done by introducing a small jet of colouring matter (say ink) into the pipe. If we see only a thin streak of the colouring matter parallel to the axis of the pipe, then the flow is steady. If the path of the colouring matter is zig - zag, then the flow is turbulent.

Question 82. What Is Bernoulli’s Theorem?

Answer :

It is found that for streamline flow, viscosity effects can be neglected. According to Bernoulli’s theorem, for a non viscous fluid a streamline flow, the total energy per unit mass remains constant.

Question 83. What Is Bernoulli’s Theorem In Terms Of Various Heads?

Answer :

For a fluid in stream line flow, the sum of pressure head, the gravitational head and the velocity head is always a constant at all points along its path.

Question 84. To Keep A Piece Of Paper Horizontal, You Should Blow Over, Not Under It. Why?

Answer :

By blowing over it, the speed of flow of air increases and hence pressure of air on it decreases slightly whereas the pressure below it is atmosphere hence the paper stays horizontal.