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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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

It is the VOLUME of the liquid FLOWING per unit TIME.

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

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.

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.

YES, but viscosity of gases is MUCH smaller (about hundred TIMES LESS) than that of a liquid.

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

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.

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.

The upward PUSH applied by the FLUID on a submerged OBJECT is known as BUOYANT force and this effect is CALLED buoyancy.

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

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.

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.

EVANGELISTA TORRICELLI in about 1644.

Evangelista Torricelli in about 1644.

<P>DEPTH, DENSITY and GRAVITY, i.e. P = HDG.

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

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.

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.

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.

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.

It is BASED on Pascal’s LAW. A hydraulic LIFT is a device used to support or lift HEAVY objects.

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

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).

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).

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.

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.

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.

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.

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.

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.

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).

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).

When GERMANIUM CRYSTAL is doped with an impurity CONTAINING five VALENCE electrons such as arsenic.

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

LOUIS DE BROGLIE.

Louis de Broglie.

The INTERNAL FORCE WITHIN the MATERIAL.

The internal force within the material.

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.

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.

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.

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.

The RATIO of CHANGE in volume to ORIGINAL volume is called volume STRAIN.

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

SHEARING STRAIN is defined as the angle of shear MEASURED in RADIANS.

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

The RATIO of CHANGING in LENGTH to ORIGINAL length.

The ratio of changing in length to original length.

The ratio of the change in shape to the ORIGINAL shape is CALLED STRAIN. There are three types of strains,

• Longitudinal
• SHEARING
• Volume

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

RESTORING force parallel to the surface per unit AREA is called tangential stress.

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

In C.G.S system parallel to the SURFACE PER unit area is called TANGENTIAL STRESS.

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

Restoring FORCE PURSUIT area PERPENDICULAR to the surface is CALLED normal stress. Its unit is N/m2.

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

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.

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.

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.

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.

It means that the wire requires a very LARGE force to PRODUCE a small CHANGE in LENGTH.

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

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.

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.

A SUBSTANCE which has DIFFERENT PROPERTIES in different directions is CALLED an anisotropic substance.

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

Because the INCIDENT LIGHT is READILY ABSORBED by the free ELECTRONS in a metal.

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

• SCANNING tunneling
• ELECTRON MICROSCOPY
• X - Ray diffraction SPECTROSCOPY

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.

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.

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.

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.

There are TWO type’s SOLIDS; crystalline solids and glassy solids (or amorphous SOLID).

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

• SOLID
• LIQUID
• GAS

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.

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.

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.

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.

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.

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.

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.

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.