SEXUAL REPRODUCTION IN PLANTS

    TO UNDERSTAND REPRODUCTION IN FLOWERS WE NEED TO KNOW THE PARTS OF          FLOWERS FIRST--

                                                                                                   

THE FOLLOWING VIDEO CONTAINS THE PROCESS OF REPRODUCTION IN FLOWERS OR SEXUAL REPRODUCTION IN PLANTS

                                                              

HOW TO MAKE RAY DIAGRAMS??

These videos show us the steps needed for making ray diagrams of-

• CONCAVE MIRRORS

• CONVEX MIRRORS

Ray diagram in convex mirror from Johnson Obina Okeny

Ray diagram in concave mirrors from Johnson Obina Okeny

NOMECLATURE

Wood Root

This denotes the number of carbon atoms present in a given molecule. For e.g., C₁-Meth, C₂- Eth, C₃ - Prop, C₄- But.

Suffix

The suffix denotes the type of bonds or the functional group present in the carbon chain, e.g.

Type of bond	Functional group
'ane' (single bond)	'ol' for alcohols (-OH)
'ene' (double bond)	'al' for aldehydes (-CHO)
'yne' (triple bond)	'oic acid' for carboxylic acid (-COOH)

Prefix

This denotes the presence of other functional groups and their position.
For e.g., the following compound can be named as:

Word root: But (C₄) Prefix: 3, chloro
Suffix: -ol Name: 3-chloro butanol
Note carbon atoms are numbered from the side of the functional group (-OH in this case).

SIGN CONVENTIONS FOR REFLECTION OF SPHERICAL MIRRORS

MIRRORS	OBJECT DISTANCE (u)	DISTANCE OF REAL IMAGE	DISTANCE OF VIRTUAL IMAGE	FOCAL LENGTH (F)	HEIGHT OF OBJECT	HEIGHT OF REAL IMAGE	HEIGHT OF VIRTUAL IMAGE
CONVEX	NEGATIVE	IMAGE DOES NOT FORM	POSITIVE	POSITIVE	POSITIVE	IMAGE DOES  NOT FORM	POSITIVE
CONCAVE	NEGATIVE	NEGATIVE	POSITIVE	NEGATIVE	POSITIVE	NEGATIVE	POSITIVE

how do organisms reproduce...................

 Asexual reproduction is a mode of reproduction by which offspring arise from a single parent, and inherit the genes of that parent only; it is reproduction which almost always does not involvemeiosis, ploidy reduction, or fertilization. The offspring will be exact genetic copies of the parent, except in the specific case of automixis. A more stringent definition is agamogenesis which is reproduction without the fusion of gametes. Asexual reproduction is the primary form of reproduction for single-celled organisms such as the archaea, bacteria, and protists. Many plants andfungi reproduce asexually as well.



source:   http://www.youtube.com/watch?v=v6osswxstfk

ALLOTROPES OF CARBON

  CARBON OCCURES IN DIFFERENT FORMS KNOWN AS ITS ALLOTROPIC FORMS.
   DIAMOND,GRAPHITE AND FULLERENES ARE SOME OF THE ALLOTROPES OF CARBON WHICH ARE EXPLAINED IN THE GIVEN VIDEO.

ALTHOUGH THEY HAVE SAME CHEMICAL PROPERTIES BUT THEIR PHYSICAL PROPERTIES ARE NOT THE SAME.


                                                                                  

                                                                                    

RAY DIAGRAMS OF CONCAVE AND CONVEX MIRRORS

1. AT INFINITY
2.B/W FOCUS AND CENTRE OF CONVATURE
3.AT CENTRE OF CONVATURE
4.B/W CENTER OF CONVATURE AND FOCUS
5.AT INFINITY
6.B/W FOCUS AND POLE

LIGHT AND REFLECTION (PHYSICS)

Reflection: Introduction

Reflection of Light Through Plane and Spherical Mirrors

Reflection is one of the unique properties of light. It is the reflection of light, which enables us to see any object.
Reflection: The bouncing back of rays of light from a polished and shiny surface is called reflection or reflection of light. It is similar to bouncing back of a football after colliding with a wall or any hard surface.

Laws of Reflection of light:

• The angle of incidence and angle of reflection is equal.
• The incident ray, reflected ray and normal to the point of reflection lie in the same plane.

The angle of incidence is denoted by 'i' and angle of reflection is denoted by 'r'.
The law of reflection is applicable to all types of reflecting surface.

Mirror and Reflection of Light

Mirror is a shiny polished object (glass) which reflects most of the rays of light falling upon it. One side of mirror is polished with suitable material to make the other side reflective.

Types of Image formed by mirrors: Real and Virtual.

Real image: Image which is formed in front of the mirror and it can be obtained on a screen is called real image.
Virtual image: Image which is formed behind the mirror and cannot be obtained on a screen is called virtual image.
Types of Mirror: Plane and spherical.
Plane Mirror: A mirror having a flat surface is called plane mirror.

Formation of image in plane mirror:

• A plane mirror always form virtual and erect image.
• The distance of image and that of object is equal from the mirror.
• The image formed by a plane mirror is laterally inverted.

Spherical Mirror: Mirrors having curved reflecting surface are called spherical mirrors. A spherical mirror is a part of a sphere.

Type of spherical mirror: Spherical mirrors are of two types - Concave and Convex.

Concave Mirror: Spherical mirror with reflecting surface curved inwards is called concave mirror.
Convex Mirror: Spherical mirror with reflecting surface curved outwards is called convex mirror.

Important terms in the case of spherical mirror:

Pole: The centre of reflecting surface of a spherical mirror is known as Pole.
 Pole lies on the surface of spherical mirror. Pole is generally represented by ‘P’.

Centre of Curvature: The centre of sphere; of which the reflecting surface of a spherical mirror is a part; is called the centre of curvature of the spherical mirror. Centre of curvature is not a part of spherical mirror rather it lies outside the mirror. Centre of curvature is denoted by letter ‘C’.
In the case of concave mirror centre of curvature lies in front of the reflecting surface. On the other hand, centre of curvature lies behind the reflecting surface in the case of convex mirror.
Radius of Curvature: The radius of sphere; of which the reflecting surface of a spherical mirror is a part; is called the Radius of Curvature of the spherical mirror. The radius of curvature of a spherical mirror is denoted by letter ‘R’.
Similar to centre of curvature, radius of curvature lies in front of concave mirror and lies behind the convex mirror and is not a part of the mirror as it lies outside the mirror.
Aperture: The diameter of reflecting surface of a spherical mirror is called aperture.
Principal Axis: Imaginary line passing through the centre of curvature and pole of a spherical mirror is called the Principal Axis.
Focus or Principal Focus: Point on principal axis at which parallel rays; coming from infinity; converge after reflection is called the Focus or Principal Focus of the spherical mirror. Focus is represented by letter ‘F’.
 
In the case of a concave mirror, parallel rays; coming from infinity; converge after reflection in front of the mirror. Thus, the focus lies in front of a concave mirror.
In the case of a convex mirror, parallel rays; coming from infinity; appear to be diverging from behind the mirror. Thus, the focus lies behind the convex mirror.
Focal length: The distance from pole to focus is called focal length. Focal length is denoted by letter ‘f’.
Focal length is equal to half of the radius of curvature.



                          source- www.excellup.com




            

CARBON AND ITS COMPOUNDS

   Carbon is a unique element which forms more compounds as compared to other elements. It is a non metal which has many other allotropic forms like carbon and graphite.The compounds of carbon are so important that the chemistry of carbon compounds form a separate branch of chemistry called organic chemistry.

                       Covalent bonds

   The compounds containing ionic or electrovalent bonds are called electrovalent or ionic compounds.For ex- NaCl

                           

                                                    but

    

 the bonds formed by sharing of electrons are called covalent compounds.

                               

                             

   Difference b/w ionic and covalent compounds

          Covalent compounds consist of molecules while ionic compounds consist  of ions

          Covalent compounds are liquids or gases at room temp. but ionic compounds are solids

    

          Covalent compounds form weak bonds but ionic compounds form strong compounds.

  

          Covalent compounds low melting and boiling compounds but ionic compounds have high melting and boiling points.

          

            Covalent compounds are generally insoluble in polar solvents and soluble in polar compounds and ionic compounds are vice versa.

            

          Covalent compounds conduct electricity but ionic compounds do not.

                   Unique nature of carbon 

   -Catenation-   the tendency to form bonds with atoms of the same element.

                         strong carbon-carbon atoms are formed

   -Tetravalency- the valency of carbon is four so it can share electrons of                        four other elements or other carbons.

  - Multiple bonds- carbon can form single,double or triple bonds

                       single bond means to share one electron

                        double bond means to share two electrons

                        triple bond means to share three electrons

  

                     HYDROCARBONS

  The organic compounds which consist of only carbon and hydrogen are called hydrocarbons.

               THERE ARE TWO TYPES OF HYDROCARBONS

      -Saturated hydrocarbons- consisting of single bond.They are also  called                      alkanes.

     -Unsaturated hydrocarbons- consisting of double bonds called alkenes

                                                     or

                                   triple bonds called alkynes.

            

                       source-  holyfaith modern abc of chemistry(book)