Section A

Q.1. Choose the correct answer :

1. Ganga Action plan was started in the year :
(b) 1985 ✔️

2. The factor responsible for ozone hole is :
(a) Aerosol ✔️

3. S.I unit of resistance is :
(b) Ohm ✔️

4. The cause of blue colour of sky is :
(b) scattering of light ✔️

5. The mirror formula of spherical mirror is :

Q.2. Fill in the blanks :

1. The full form of R.N.A. is Ribonucleic acid .

2. Blinking of eyes is reflex action.

3. The respiration in fishes is through Gills .

4. The properties of elements are periodic function of their Atomic number .

5. The metal Mercury .

Q.3. Match the columns :

Q.4. Answer the following in one word one/sentence :

1. What is the chemical formula of quick lime ?
ans. CaO

2. Who gave the theory of natural selection ?
ans. Charles Darwin

3. What is least distance of distinct vision for human eye ?
ans. 25cm.

4.what is function of MnO2 in dry cell ?
ans. Depolarizer

5. what is name of pollutants which are not decomposed by microorganism ?
ans. Non-biodegradable.

Section B

Q. 5. Why we paint the things made of iron ?
Ans. We apply paint on iron articles because paint act as antioxidant and saves iron from corrosion.
    oil and fat containing food items are flushed with nitrogen. why 
Ans. When the oil and fat containing food items comes into contact with the air they get oxidized. to keep these items save from oxidising effect, they are flushed with nitrogen .

Q.6. Write names of elements of zero group.
Ans. Helium, Neon, Argon, Krypton, Xenon, Radon.
   write the following halogens in increasing order of their reactivity ;
                              Br, I, Ci, F.
Ans. I<Br<CI<F.

Q.7. How it is possible to control fertilization ? Explain.
Ans. Fertilization can be controlled when ovum lies in the uterus for fertilization for a short time. By the help of various chemical and surgery the fusion of sperm and ovum can be prevented. These to methods are used to control population.
(i) Increase in population can be checked.
(ii) Family planing helps greatly towards family welfare.
(iii) Population of the country will be controlled, thus aims of five years planing, education and other facilities of each child will be become successful.
     What is meant by pollination ? How many types of pollination
Ans. Pollination : The process of transfer of pollen grains from another of stamen (Androecium ) to stigma of pistil is called pollination.
Types of pollination: (i) Self pollination. (ii) Cross pollination.

Q.8. What factors could lead to the rise of a new species ?
Ans. (i) Natural selection.
(ii) The low occurrence or no occurrence of levels of gene flow.
(iii) Such type of sepration between two sub population that their members can not execute mutual reproduction.
(iv) The change in D.N.A.
 What are the different ways in which individuals with a particular traits may increase in a population ?
Ans. (i) By naturals selection the individual with a particular trait may increase in population.
(2) The sudden hazard in  population may increase the particular traits.

Q.9. State law of reflection.
Ans. (i) The angel of reflection is always equal to the angel of incidence.
(ii) The incident rays, reflected rays and the normal, all lie in the same plane.
Write law of refraction.
Ans. There are two laws of refraction:
(i) The incident rays, refracted ray and the normal at the point of incidence all lie in the same plane.
(ii) The ratio of the sine of angel of incidence to the sine of angel of refraction is constant for a given pair of medium i.e,. if angel of incidence is represented by i and angel of refraction by r , then

Section c

Q.10.  State any two factors affecting the rate of reaction.
Ans.  The following are the factors which affecting the rate of reaction.
(1)Concentration : Rate of reaction increases with increase in concentration of the reactants.
(2) Temperature : Normally at high temperature, rate of chemical reaction is high.
Why are decomposition reaction called the opposite of combination reactions ?
Ans. In a decomposition reaction, a single reactant breaks down to give simpler products.


But in a combination reaction is opposite two more reactants. combine together from a simple product.


Thus,it is clear that decomposition reaction is opposite to the combination reaction.

Q.11. What is mean by rarer and denser medium ?
Ans. Different between denser and rarer medium:

Why the trunks of tree and roads appear shaking during summer ?
Ans. during summer days, roads become hot which in turn expand the air in contact with it anjd make it rarer. Air near the road is more rarer and the far off air becomes more denser. This way, layer's of air is formed which goes on changing. Therefore due to mirage (Total internal reflection ) position of images of roads and trees goes on changing.
   That is why, the trunks of trees and roads appear shaking during summer.

Q.12. Define induced current. Why they are produced?93
Ans. The current produced in a coil due to relative motion between the coil and the magnet is called induced current.
 Due to relative between the coil and magnet the flux linked with coil changes. Hence the induced current is developed.
  What is electric fuse ? Write its uses.
Ans. It is a device in which the wire of an alloy of high resistance and low melting is used which controls the maximum limit of electric current following through a circuit. It is used to present the electrical appliances by short circuiting and overloading.

Q.13. How is good fuel selected ?
Ans. (i) High calorific value .
(ii) Proper ignition temperature,
(iii) Balanced rate of combustion,
(iv) Easily available, 
(v) low percentage of non combustion materials.
 What do you understand by chain reaction ?
Ans. Chain Reaction: When U235 atom is bombarded with a neutron, it gets fissioned to produced two light nuclei and huge amount of energy is released along with three neutrons. these three neutron in turn, cause the fission of other uranium atoms and this way the reaction multiples. This multiple reaction is called chain reaction.  

Q.14. Plaster of paris should be stored in moisture proof container. explain why.
 Ans.When the plaster of paris comes in contact with moisture, it absorbs water and converted into Gypsum and get deposited in the vessel. So it is kept in moisture proof container. 
How is the concentration of hydroxide ions (OH) affected when excess base is dissolved in a solution of sodium hydroxide ?
Ans. When the excess base is dissolved in a solution of sodium hydroxide then the concentration of OH ion is increased.

Q.15. What is homologous series ? explain with example.
 What change will you observe if you test soap with litmus paper ( red or blue ) ?

Q.16. Give difference between the respiration of plants and animals.
 Write difference between photosynthesis and respiration.

Q.17. Write the functions of forebrain.
Write any four functions of cytokinin.

Q.18. What are amphoteric oxides ? Give two examples of amphoteric oxide.
What would you observe when zinc is added to a sodium of iron (ii) sulphate ?
write the chemical reaction that take place.

Q.19. Write five difference between pollination and fertilization.  
Write down difference between sexual and asexual reproduction.