9th SCIENCE and Mathematics NCERT SOLUTIONS

A. Answer these questions 1. Name the three life process help living being to procure energy from food? Answer: Three life processes that help living organisms to procure energy from food are: (i) Digestion (Nutrition) (ii) Respiration (iii) Transportation 2. What are Autotrophs? Name an organism other than other than green plant that is an autotroph. Answer: Autotrophs are organisms that can prepare their own food. Chlamydomonas is a type of green algae which is an example of an autotroph, other than green plants. Cyanobacteria are also an example of autotroph. 3. Name three type of heterotrophic nutrition Answer: Three types of heterotrophic nutrition are: (i) Saprophytic nutrition (ii) Parasitic nutrition (iii) Holozoic nutrition 4. What are enzymes? Answer: Enzymes are chemical substances that act as biological catalysts and are important for carrying out biochemical processes, such as digestion, in our body ...

VI (6th) Fun with Magnets MCQ’s

October 23, 2012

CBSE - Class 6 - Science Chapter :Fun with Magnets Multiple choice Questions (1) When a magnet is suspended freely it always aligns itself in -------- direction? a) North b) N-S c) N-W d) N-E (2) ---------- is the only natural magnet. a) Magnetite b) Ebonite c) Cobalt d) Nickel (3) Which of the following cannot be used to make a magnet? a) Cobalt b) Iron c) Ebonite d) Steel (4) Which of the following is not a non-magnetic substance? a) Glass ...

Class9 Biology chapter Cell the Fundamental unit of life :Assignment solved

April 12, 2015

1. What is plasma membrane? What are their functions? Ans: Plasma membrane also called as cell membrane, is the outer covering of a cell that separates the cell contents (protoplasm) from the surrounding medium. It is made up of proteins and lipids. It gives form (shape and size) to the cell It maintains the individuality of the cell (i.e. seperates cells) It keeps the cell contents in place 2. What are cell organelles ? Ans: The certain specific living parts of a cell with a definite function are celled Cell organelles. All cell are found to have same organelles and together these constitute to the basic unit of life. 3. What is cellulose and its functions? Ans: Cellulose is the main component of a plant cell wall. It is responsible for giving structural shape to the cell and also to protect the protoplasm. 4. What is a Prokaryotic cell? Give an Example. Ans: The cells that do not hav...

IX Biology:Extra marks Guess Solved Question paper : Cell and its Function

June 16, 2012

IX The Cell & Fundamental Unit of life Question : Why is the cell known the 'fundamental and structural unit of life ' Ans: ell is called as the structural and functional unit of the living organism because it the smallest living entity that is capable of an independent existence. Separated cell organelles cannot be said to be living and are not capable of independent existence. Question : what is a semi permeable membrane? what are the differences between semi permeable membrane and selectively permeable membrane? Ans: a semi permeable membrane is a membrane that allows only the entry of substances that are helpful for the body. a semi permeable membrane is also called a selectively permeable membrane. Question : Which cell in the human body does not have the mitochondria? Ans: Mature erythrocytes don't have mitochondria Question : What are plastids? Write their functions? Ans: Plastids are double membrane organelle...

Derivation of Lens and mirror formula X Reflection and Refraction of light

November 29, 2013

MIRROR FORMULA The relation between object distance(u), image distance(v) and the focal length (f) of the mirror is known as MIRROR FORMULA. Consider a concave mirror MM' (of small aperture). An object AB of height h is placed on the left of the mirror beyond its center of curvature so that the image formed is real, inverted and diminished in size(height = h'). Here : Object distance = PB = -u Image distance = PB'= -v Focal length = PF = -f Radius of curvature = PC = -R As shown in Figure, Δ ABP ∼ Δ A'B'P. ∴ A'B'/AB = PB'/PB ∴ A'B'/AB = (-v)/(-u) ∴ A'B'/AB = v/u.............(I) Similarly, as shown in the figure, Δ ABC ∼ Δ A'B'C. ∴ A'B'/AB = CB'/CB ∴ A'B'/AB = (PC-PB')/(PB-PC)........[as CB'=(PC-PB') and CB=(PB-PC)] ∴ A'B'/AB = [-R - (-v)]/[-u - (-R)] ∴ A'B'/AB = (-R + v)/(-u + R)........(II) By (I) & (II), v/u = (-R + v)/(-u + R) ∴ -...

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