UT - 2 SYLLABUS / CLASS 9

PT -2     SYLLABUS

CLASS 9     (2019-20)

HINDI

स्पर्श :धर्म की आड़,  कीचड़ का काव्य,   आदमीनामा      

संचयन :मेरा छोटा सा निजी पुस्तकालय

व्याकरण :उपसर्ग, प्रत्यय, संधि

लेखन :विज्ञापन

अपठित गद्यांश

ENGLISH

Reading. Section

Writing Section

Article Writing

Diary Entry

Story Writing 

Beehive 

Packing

The duck and the Kangaroo

Reach for the top

On killing tree

Supp. Book - Lesson 5

MATHS

CHAPTER- 7 – TRIANGLES

CHAPTER -8 – QUADRILATERALS

CHAPTER-13- SURFACE AREA AND VOLUME

SST

HISTORY- FOREST SOCIETY AND COLONIALISM

GEOGRAPHY- NATURAL VEGETATION AND WILDLIFE.

CIVICS- ELECTORAL POLITICS

ECONOMICS- POVERTY AS A CHALLENGE

SCIENCE

PHYSICS-CHAPTER -10 -GRAVITATION (BUOYANCY)

CHAPTER -11 - WORK AND ENERGY.

CHEMISTRY-ATOMS AND MOLECULES

BIOLOGY-WHY DO WE FALL ILL?

PT -2     SYLLABUS

CLASS 9     (2019-20)

HINDI

स्पर्श :धर्म की आड़,  कीचड़ का काव्य,   आदमीनामा      

संचयन :मेरा छोटा सा निजी पुस्तकालय

व्याकरण :उपसर्ग, प्रत्यय, संधि

लेखन :विज्ञापन

अपठित गद्यांश

ENGLISH

Reading. Section

Writing Section

Article Writing

Diary Entry

Story Writing 

Beehive 

Packing

The duck and the Kangaroo

Reach for the top

On killing tree

Supp. Book - Lesson 5

MATHS

CHAPTER- 7 – TRIANGLES

CHAPTER -8 – QUADRILATERALS

CHAPTER-13- SURFACE AREA AND VOLUME

SST

HISTORY- FOREST SOCIETY AND COLONIALISM

GEOGRAPHY- NATURAL VEGETATION AND WILDLIFE.

CIVICS- ELECTORAL POLITICS

ECONOMICS- POVERTY AS A CHALLENGE

SCIENCE

PHYSICS-CHAPTER -10 -GRAVITATION (BUOYANCY)

CHAPTER -11 - WORK AND ENERGY.

CHEMISTRY-ATOMS AND MOLECULES

BIOLOGY-WHY DO WE FALL ILL?

PT -2     SYLLABUS

CLASS 9     (2019-20)

HINDI

स्पर्श :धर्म की आड़,  कीचड़ का काव्य,   आदमीनामा      

संचयन :मेरा छोटा सा निजी पुस्तकालय

व्याकरण :उपसर्ग, प्रत्यय, संधि

लेखन :विज्ञापन

अपठित गद्यांश

ENGLISH

Reading. Section

Writing Section

Article Writing

Diary Entry

Story Writing 

Beehive 

Packing

The duck and the Kangaroo

Reach for the top

On killing tree

Supp. Book - Lesson 5

MATHS

CHAPTER- 7 – TRIANGLES

CHAPTER -8 – QUADRILATERALS

CHAPTER-13- SURFACE AREA AND VOLUME

SST

HISTORY- FOREST SOCIETY AND COLONIALISM

GEOGRAPHY- NATURAL VEGETATION AND WILDLIFE.

CIVICS- ELECTORAL POLITICS

ECONOMICS- POVERTY AS A CHALLENGE

SCIENCE

PHYSICS-CHAPTER -10 -GRAVITATION (BUOYANCY)

CHAPTER -11 - WORK AND ENERGY.

CHEMISTRY-ATOMS AND MOLECULES

BIOLOGY-WHY DO WE FALL ILL?

PT -2     SYLLABUS

CLASS 9     (2019-20)

HINDI

स्पर्श :धर्म की आड़,  कीचड़ का काव्य,   आदमीनामा      

संचयन :मेरा छोटा सा निजी पुस्तकालय

व्याकरण :उपसर्ग, प्रत्यय, संधि

लेखन :विज्ञापन

अपठित गद्यांश

ENGLISH

Reading. Section

Writing Section

Article Writing

Diary Entry

Story Writing 

Beehive 

Packing

The duck and the Kangaroo

Reach for the top

On killing tree

Supp. Book - Lesson 5

MATHS

CHAPTER- 7 – TRIANGLES

CHAPTER -8 – QUADRILATERALS

CHAPTER-13- SURFACE AREA AND VOLUME

SST

HISTORY- FOREST SOCIETY AND COLONIALISM

GEOGRAPHY- NATURAL VEGETATION AND WILDLIFE.

CIVICS- ELECTORAL POLITICS

ECONOMICS- POVERTY AS A CHALLENGE

SCIENCE

PHYSICS-CHAPTER -10 -GRAVITATION (BUOYANCY)

CHAPTER -11 - WORK AND ENERGY.

CHEMISTRY-ATOMS AND MOLECULES

BIOLOGY-WHY DO WE FALL ILL?

light : refraction notes / class 10

Refraction of Light

Refraction of Light : Happens in Transparent medium when a light travels from one medium to another, refraction takes place.
A ray of light bends as it moves from one medium to another Refraction is due to change in the speed of light as it enters from one transparent medium to another.

Speed of light decreases as the beam of light travel from rarer medium to the denser medium.

Some Commonly observed phenomenon due to Refraction

• Your eyes.
• Rainbows.
• Light bending in a glass of water.

• Glasses.
• Camera lenses.
• Object dislocation in water.

 Refraction through a Rectangular Glass Slab

•  

When a incident ray of light AO passes from a rarer medium (air) to adenser medium (glass) at point. O on interface KL, it will bends towards the normal. At ptO1, on interface NM the light ray entered from denser medium(glass) to rarer medium (air) here the light ray will bend away from normal OO1 is a refracted ray OB is an emergent ray. If the incident ray is extended to C, we will observe that emergent ray O1B I parallel to incident ray. The ray will slightly displaced laterally after refraction.

Note : When a ray of light is incident normally to the interface of two media it will go straight, without any deviation.

Laws of Refraction of Light

The incident ray, the refracted ray and the normal to the interface of two transparent media at the point of incidence, all lie in the same plane.

The ratio of sine of angle of incidence to the sine of angle of refraction is a constant i.e.

• 

For given colour and pair of media, this law is also known as Snell’s Law

Constant n is the refractive index for a given pair of medium. It is the refractive index of the second medium with repect to first medium.

Refractive Index

The refractive index of glass with respect to air is given by ratio of speed of light in air to the speed of light in glass.

c Speed of light in vacuum =  speed of light in air is marginally less, compared to that in vacuum.

Spherical Lens

A transparent material bound by two surfaces, of which one or both surfaces are spherical, forms a lens.

Convex lens / Concave lens
1. Bulging outwards - convex -Converging lens 

2. Bulging inwards - concave - Diverging lens.

 

Few Basic Terms Related to Spherical Lens

1. Centre of curvature : A lens, either a convex lens or a concave lens is combination of two spherical surfaces. Each of these surfaces forma part of sphere. The centre of these two spheres are called centre of curvature represented by C1 and C2.
2. Principal axis :Imaginary straight line passing through the two centres of curvature
3. Optical Centre : The central point of lens is its optical centre (O). A ray of light, when passes through ‘O’ it remains undeviated i.e. it goes straight.
4. Aperture : The effective diameter of the circular outline of a spherical lens.
5. Focus of lens : Beam of light parallel to principal axis, after refraction from

1. Convex lens, converge to the point on principal axis, denoted by F, known as Principal focus

2. Concave lens, appear to diverge from a point on the principal axis known as principal focus.

The distance OF2 and OF1 is called as focal length

Tips for Drawing Ray Diagram

1. After refraction, a ray parallel to principal axis will pass through F.
2. A ray passes through F, after refraction will emerge parallel to principal axis
   

Image formation by a convex lens for various position of object

   

 

Image Formation by Concave Lens

Sign Convention for Refraction by Spherical Lens

Similar to that of spherical mirror, only the difference is that all themeasurement are made from optical centre ‘O’

Lens formula

Magnification

It is defined as the ratio of the height of image to the height of object.

It is also related to ‘u’ & ‘v’

From equation (1) & (2)
If magnification
m > 1,then image is magnified
m = 1 ,image is of same size
m < 1, image is diminished

Few Tips to Remember Sign Convention for Spherical Lens

	f	u	v
CONCAVE	-ve	-ve	-ve(virtual image always)
CONVEX	+ve	-ve	+ve(real) -ve(virtual)

h is always +ve
h´  –ve for Real and +ve for Virtual &Errect.

Power of Lens

The degree of convergence or divergence of light ray achieved by a lensis known as power of a lens.
It is defined as the reciprocal of its focal length Represented by P.
If F is given in meter, then

If F is given in cm , then

SI unit of power of a lens is “diopter” denoted by ‘D’
I diopter or ID  It is the power of lens whose focal length is I m

Power of convave lens or diverging lens is always negative

If any optical instrument has many lens, then net power will be

class 10 / lab activities / physics

Activity -4

To study the field lines formed around a bar magnet

Objective

To study field lines formed around the bar magnet.

Theory

• Magnets have two types of poles: north poles and south poles.
• The magnetic strength at the pole is the strongest.
• When a bar magnet is suspended freely in a horizontal position, the bar magnet will align itself in north-south direction, where the north pole of the magnet points to the north pole of the Earth.
• Like poles repel and unlike poles attract.
• Magnetic materials such as iron, nickel, steel etc. are attracted by the magnets.
• Attractive and repulsive force of magnet depends how strong the magnet is.
• Magnetic force also depends on distance between the magnet and the object.

Materials :

White paper sheet, drawing board, adhesive, bar magnet, iron filings and magnetic compass.

Procedure :

1.    Fix a sheet of white paper on a drawing board using some adhesive material.

2.    Place a bar magnet in the center of it.

3.    Sprinkle some iron filings uniformly around the bar magnet.

4.    Now tap the board gently.

5.    Observe the pattern in which the iron filings arrange themselves.

Observation

1.    The strength of the magnetic field is inversely proportional to the distance between the field lines.

2.    Magnetic field lines never cross each other. It is unique at every point in space.

3.    Magnetic field lines begin at the north pole of a magnet and terminate on the south pole.

Activity -5

Magnetic field lines around current carrying conductor

Objective: 

To observe the magnetic field lines around current carrying conductor.

Theory:

1. Magnetic effect of electric current is one of the major effects of electric current in use, without the applications of which we cannot have motors in the existing world.
2. A current carrying conductor creates a magnetic field around it, which can be comprehended by using magnetic lines of force or magnetic field lines.
3. The nature of the magnetic field lines around a straight current carrying conductor is concentric circles with centre at the axis of the conductor.
4. The strength of the magnetic field created depends on the current through the conductor.
5. The direction of the magnetic field lines of force around a conductor is given by the Maxwell’s right hand grip rule or the right handed corkscrew rule.​ ​Imagine that you are holding a current-carrying straight conductor in your right hand such that the thumb points towards the direction of current. Then your fingers will wrap around the conductor in the direction of the field lines of the magnetic field​. This is known as right hand thumb rule.

Apparatus:

A battery (12 V), a variable resistance (or a rheostat), an ammeter (0–5 A), a plug key, and a long straight thick copper wire.

Procedure:

1. Fix the cardboard and insert the wire through the centre of cardboard such that it is normal to its plane.
2. Connect the wire with rheostat, ammeter, battery and plug key in series.
3. Sprinkle the iron filings uniformly on the cardboard.
4. Keep the variable of the rheostat at a fixed position and note the current through the ammeter.
5. Close the key and gently tap the cardboard.
6. Observe the pattern of the iron filings over the cardboard.

Observations

1.    You will observe that the magnetic field lines are formed in concentric circles around the current carrying conductor. These lines do not intersect each other and are equidistant from each other.

2.    The direction of the field is perpendicular to the conductor.

3.    The magnetic field (B) acting on the object O increases as the current flowing through it increases.

4.    The field increases as object O is closer to the conductor and decreases as it moves away from the conductor.

5.    The direction of magnetic field lines gets reversed if the direction of current is reversed.

Activity -6

Force on a current carrying conductor in a magnetic field

Objective:

To study the force on a current-carrying straight conductor in a magnetic field and to verify that the motion of the conductor is according to Fleming’s left-hand rule.

Theory:

A current carrying conductor placed in a magnetic field experiences a force. If the direction of the field and that of current are mutually perpendicular to each other, then the force acting on the conductor will be perpendicular to both and that can be determined using the Fleming’s left-hand rule. When current establishes in the conductor, it gets displaced which verifies the existence of a force on the conductor.  

  Fig. -  A current-carrying rod, AB, experiences a force perpendicular to its length and the magnetic field

 Fig. -  Fleming’s left hand rule.

Apparatus: 

A horse shoe magnet, a small aluminium rod, an ammeter, two wooden stands, two connecting wires, a battery, a plug key.

Procedure:

1. Suspend the aluminium rod horizontally from the stand using clean connecting wires.
2. Place the horse-shoe magnet in such a way that the rod lies in between both the poles such that south pole is vertically above and north pole is vertically below the rod.
3. Connect the rod in series to the battery, key and the rheostat.
4. Now switch on the current and observe the displacement of the rod.
5. Reverse the direction of the current and observe the change in the displacement of the rod. 

Observation:

On passing current through a straight conductor (aluminium rod) kept in a magnetic field, the conductor gets displaced upward or downward.

Inference:

1. The direction of displacement of the conductor rod changes with the change in the direction of current through it.
2. The displacement of aluminium rod is in accordance with Fleming’s left-hand rule.

Activity -7

Electromagnetic Induction

Objective:

To study the phenomenon of electromagnetic induction.

Theory:

The phenomenon of electromagnetic induction is the existence of an induced current in a circuit (such as a coil) placed in a region where the magnetic field motion changes with the time. The magnetic field may change due to relative motion between coil and magnet placed near the coil as shown in the Fig. 1. We know that a current-carrying conductor also produces magnetic field that changes with a change in the current flowing through it. Thus if a coil is placed near to a current-carring conductor, an induced current in the coil may setup  due to a change in the current through the current-carrying conductor.

Fig.: Moving a magnet towards a coil sets up a current in the coil circuit,

as indicated by deflection in the galvanometer needle. 

Apparatus:

Magnetic bar, a galvanometer, coil and connecting wires.

Procedure: 

1. Take a coil of wire having a large number of turns.
2. Connect the end of the coil to a galvanometer.
3. Take a strong bar magnet and move its north pole into the coil and observe the changes in the galvanometer needle.
4. Repeat earlier step with the south pole of the bar magnet.
5. Now repeat the procedure with the coil having a different number of turns and the variation in the deflection of the galvanometer needle.

Observations:

1. When we move the magnet in or out of the coil, the needle of galvanometer gets deflected in different directions.
2. When we insert the north pole (N) of bar magnet into the coil, the needle gets deflected in negative direction.
3. When we insert the south pole (S) of bar magnet into the coil, the needle gets deflected in positive direction.
4. When we move the bar magnet in or out of the coil with varying speed, the speed of deflection changes accordingly.
5. As we increase the number of turns in the coil, the deflection increases.

Inference:

1. The deflection of galvanometer needle indicates the presence of current in the coil.
2. The direction of deflection gives the direction of flow of current.
3. The speed of deflection gives the rate at which the current is induced.
4. The deflection in galvanometer changes with the change in number of turns in the coil - more the number of turns in the coil greater is the deflection.

Activity -8

To find focal length of a Concave Mirror

Objective -

To determine the focal length of a concave mirror, by obtaining image of a distant object.

Theory

1. A concave mirror, like a plane mirror, obeys the laws of reflection of light.
2. Rays of light from object - The rays of light coming from a distant object e.g. sun or a distant building can be considered to be parallel to each other. When these parallel rays of light fall on a concave mirror along its axis, reflect and meet at a point in front of the mirror, which is called as Principal focus of the mirror.
3. A real, inverted and very small image size is formed at the focus of the mirror.
4. Focal Length - The distance between the pole P of the concave mirror and the focus F is the focal length of the concave mirror. Thus, the focal length of a concave mirror can be estimated by obtaining a 'Real image' of a distant object at its focus, as shown in the figure.

​
    

Material Required -

A concave mirror, a mirror holder, a white screen fixed on a stand or a white wall, an object (candle) and a metre scale.

Procedure - 

1.    Fix concave mirror to mirror holder and place it on table.Turn the face of mirror towards a distant object (a candle in this case). The selected object should be visible with your naked eyes.

2.    Adjust the position of the screen in such a way that it forms a clear image of the candle on the screen.

3.    Measure the distance between the concave mirror and the screen with a metre scale. Record your observations in observation table. 

4.    Repeat the experiment two or three times and find the mean value of the focal length.​

NOTE: STUDENTS WE WILL DRAW THE TABLE IN SCHOOL WHILE PERFRMING THE EXPERIMNT AND WRITE RESULT SIMULTANEOUSLY. 

Activity -9

To study reflection in concave mirror

Objective:

To study reflection in concave mirror and observe image formations for different positions of the object.

THEORY

1. Reflection:
   Whenever light, travelling in one medium, comes in contact with surface of another medium, a part of it is returned into the first medium. The phenomenon of returning of light into first medium is known as reflection of light.
2. Concave mirror:
   A concave mirror is that spherical mirror in which the reflection of light takes place at the concave surface i.e. bent-in surface.
3. Pole:
   It is the center of the reflecting surface of the concave mirror also called vertex of mirror, generally denoted by letter ‘P’.
   
   
4. Center of curvature:
   It is the center of that sphere of which the concave mirror forms a part, denoted by letter ‘C’.
5. Principal axis:
   The straight line passing through the center of curvature and pole of  concave mirror is called its principal axis.
6. Principal focus:
   A beam of light incident parallel to the principal axis, after reflection from the spherical mirror, either actually converges to or appears to diverge from a fixed point on the principal axis. The fixed point is called the ‘Principal focus’, denoted by letter 'F'.
7. Laws of Reflection:
   1)    The angle of incidence is equal to the angle of reflection.
   2)    The incident ray, the reflected ray and the normal at the point of incidence, all lie in the same plane. 
8. Types of images:
   1)    Real image: If the reflected rays actually meet at a point, then the image formed is real. It can be obtained on screen.
   2)    Virtual Image: If the reflected rays do not actually meet at a point but appear to diverge from a point, then the image formed is virtual.

 Images of an object, formed by a concave mirror, when the object is placed at various positions:

When object is at infinity.	When object is beyond centre of curvature('C').
When object is at centre of curvature ('C').	When object is between 'C' and 'F'.
When object is at focus 'F'.	When object is between 'P' and 'F'.

Materials required:

A concave mirror, a mirror holder, a semi transparent screen fixed to a stand and a small candle with stand.

Procedure

1. Fix the concave mirror in the mirror holder and place it on edge of the table.
2. Mount a small candle vertically on a stand. Place it in front of the concave mirror on the left hand side (i.e. shiny surface) say on focus 'F'.
3. Place the screen such that the lower level of screen must be so arranged that it remains just above the principal axis of the mirror. 
4. Locate a sharp image of candle by adjusting the position of the screen. Note and record the position and nature of the image formed on the screen. 
5. Repeat the experiment by placing candle at different positions .

Activity -10

To study refraction of light in rectangular glass slab

OBJECTIVE: To trace the course of different rays of light through a rectangular glass slab at different angles of incidence, measure the angle of incidence, refraction and verify Snell`s law. Also measure the lateral displacement.

Apparatus:

A drawing board, rectangular glass slab, office pins, sheet of white paper, a protractor and sharply pointed pencil.

Procedure:

1. Fix a sheet of white paper on a drawing board with drawing pins. Place the given glass slab nearly in the middle of the sheet.
2. Mark the boundary of the glass slab with a sharp pencil and label it as PQRS after removing the slab from its position.
3. On the line PQ mark a point E and draw a normal N1EN2 at it. Draw a line AE making angle AEN1 with the normal.The angle should neither too small nor too large (say about 40 degree).
4. Now place the glass slab again on its boundary PQRS and fix two pins A and B vertically about 10 cm apart on the line AE (say points A and B).
5. Look through the glass slab along the plane of the paper from the side SR and move your head until the images of the two pins A and B are seen clearly. Closing your one eye ,adjust the position of your head in such a way that the images of the pins A and B lie in the same straight line.
6. Fix two other pins C and D vertically in such a way that the images of the pins A and B and pins C and D, all these four, lie in the same straight line. Ensure that the feet of the pins ( not their heads ) lie in the same straight line.
7. Remove the slab and also the pins from the board and encircle the pin-pricks on the paper,with a sharp pencil.
8. Join the points D and C and produce the line DC towards the slab so that it meets the boundary line RS at the point F. Join the points e and F. Thus for the incident ray represented by line AE, the refracted ray and the emergant ray are represented by EF and FD respectively.
9. On the line RS draw a normal N1'FN2'  at point F. Now, with a protractor, measure angle AEN1, angle FEN2 and angle DFN2' labelled as angle i, angle r and angle e respectively. 
10. Now place the glass slab at some other position on the sheet of paper fixed on the board and repeat all the above steps again taking another angle of incidence.
11. Measure the angle of incidence i.e angle of refraction, angle of emergence, again.
12. Make a record of your observations in the observation table as shown below.

 Observation Table :