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Question paper 1
Part-A
Each questionof Part-A carries 1 mark
1. Why is repiration called an exothermic reaction ?
Answer:
Respiration is known as exothermic reaction because energy is released during this process.
2. In the diagram shown below what type of organs are shown in relation in relation to evolution ?
Answer:
Analogous Organs
3. which defect of the eye is shown in the figure given below ?
Answer:
Diagram
Defect: Hypermetropia
4. Label (1) and () in the given figure.
Diagram
Answer:
5.
The above chemical equation is an example of which type of chemical reaction?
(a) Combination reaction (b) Decomposition reaction
(c) Displacement reaction (d) Double Displacement reaction
Answer:
(d) Double Dis placement reaction
Part-B
Each question of Part-B carries 2 marks
6. What happens at the synapse between two neurons?
Answer:
Synapse : Synapse is a narrow gap containing communicating junction between two narrow where Axon terminal comes near to dendrite of next narrow .
Diagram
7. Label (1) and (2) in the figure given below;
Answer:
1
2
Thyroid gland (in the neck ) 8. Find the power of a concave lens of Focal length 2 (two) metres.
Answer:
Focal length (F) = 2m
Power of lens =
=
Power of lens -0.5D
9. Write characteristics of magnetic field lines
Answer:
(i) Magnetic field lines always starts from North pole and end at South pole .
(ii) The strength of magnetic field lines is depend upon degree of Closeness.
(iii) Two magnetic field lines cannot intersect each other .
10. Which gas is being produced during reaction in the test tube? How does the gas react with Calcium Hydroxide/lime water?
Answer:
Carbon dioxide gas is produced during this reaction .
11. Why should curd and sour substances not be kept in brass and copper utencils/vessels?
Answer:
When card or sour substances are kept in copper or brass vessels it reacts with copper and forms toxic compounds which may unfit for human consumption and may cause food poisoning.
12. (i) Write molecular formula of butane.
(ii) Draw the structure of propanal.
Answer:
(i) Molecular formula of Butane :
Diagram
(ii) Propanal
Diagram
13. Write Mendeleev's Periodic law of classification of elements.
Answer:
Mendeleev Periodic law : It states that “the properties of elements are periodic function of their atomic masses.
14. How do
(i) Atomic size and
(ii) Metallic character, change in a group of Modern Periode table on going top to bottom.
Answer:
(i) Atomic size: Varies Top to Bottom.
Atomic size increases because increase in atomic radius due to increase in no: of shells.
Diagram
(ii) Metallic Character : Varies top to bottom
Atomic size increases with increase in no. of shell. Therefore Metallic character increases down the group.
15. What are the components of the transport system in highly organised plants? How does the transport of water and mineral take place in such plants
Answer:
In highly organized plants , Vascular tissues ( Xylem and Phloem) are the main components of transportation system . In general Xylem carries the water and Minerals from root to upper part and phloem carries food from leaves to other parts
Part-C
Each question of part-A carries 3 marks
16. In the figure which law is shown? Label (1) and (2) in relation to the law shown.
Diagram
Answer:
In the figure flaming left Hand Rule is shown
1
Field2
Current17. Write the characteristics of an ideal source of energy.
Answer:
Characteristics of ideals source of energy:
(i) An ideal source is one which has high calorific value.
(ii) Which has proper ignition temp.
(iii) Which burns without giving out any smoke or harmful gases
(iv) Which burns smoothly and does not leave any residues.
(v) Which is easy to handle , easy to transport.
18. What are decomposers? What is the role of decomposers in the ecosystem?
Answer:
Decomposers are the animals which feed on dead plants and animals . They are known as Environmental cleaners
Role of Decomposers : They have a huge role in the eco system as they clear the dead remaining bodies and make manure for trees.
19. What changes would you suggest in your home in order to be enironment friendy?
Answer:
Changes we would see in order to be environmental friendly:
(i) By Sanitation
(ii) By using 3Rs formula (Reduce, Reuse, Recyde)
(iii)By not wasting the water
(iv) By not wasting the electricity.
(v) By avoiding much use of Bikes, Cars, etc.
(vi) using Bicycles for short distances.
(vii) By growing more and more trees.
20. Write a chemical equation for the reaction place in the test tube, How does the colour of solution change? What is change in the colour of iron nails?
Answer:
(blue) (green) reddish brown
This is displacement reaction. In which Fe displaces Cu and from new substance which have different properties and color. Iron nails become green in colour . when combine with sulphate.21. Name the compound shown in the figure. How many single covalent bonds are present in it? To which series of Hydrocarbons does this compound belong?
Diagram
Answer:
Diagram
Ethene. 4 single covalent bonds are present . This is called unsaturated Hydrocarbon and belongs to ethane family.22. Write three differences between Aerobic and Anaerobic respiration.
Answer:
Aerobic Respiration
(i) It takes place in the presence of oxygen
(ii) Glucose is breakdown with the help of
(iii) The end products are
and 
Anerobic Respiratio
(i) It takes place in the absence of oxygen
(ii) Glucose is breakdown with the help of
(iii) The end products are may be ethyl alcohol
and lactic aid23. What are fossils? What do they tell us about the process of evolution?
Answer:
Fossils : These are the dead remains of animals buried deep under the soil which are basically impression of post animals million year ago.
Formation of fossils is known as fossilization These fossils provide the evidence that present animals and plants have originated from previously existing ones thought the process of continuous evolution
24. Which mirror is shown in the diagram? Where is object placed in relation to the mirrior? write characteristics of the immage formed:
Diagram
Answer:
Diagram
This is a CONCAVE MIRROR The object is placed beyond ‘C’ centre of curvature Characteristics : *
The image is of small size. The image is real and invertedThe image is formed between C and F.25. Why does the colour of the sky appears blue?
Answer:
When sunlight passes thought the atmosphere most of the longer wavelength lights [Red,Orange,Yellow,etc] do not scattered much by the air molecules. The Shorter wavelength blue light is scattered all around the sky by air molecules, whichever direction we look some of this scattered blue light enters owl eye from everywhere overhead the sky look blue.
Part-D
Out of question number 26,27,28 of Part-D, attempt one question each.
26. Draw a labelled diagram of vertical section of a flower and explain its various parts.
Answer:
Diagram
OR
26. What changes are seen among the girls during adolescent age/puberty?
Answer:
Various change in girls during adolescent age / Puberty are:
(i) Hair grow under armpits and public region.
(ii) Mammary glands or breasts develop and enlarge.
(iii) The hips starts broaden
(iv) Extra fat is deposited on different parts like hips and things
(v) Fallopian tube, uterus and vagina enlarge. Ovaries start to release egg.
(vi) Menstruation begin to start.
Qestragen and Progesterone are responsible for these.27. Write Ohm's law. Draw a circuit diagram to prove it experimentally in the laboratory.
Answer:
Ohm’s law :It states that at some physical condition the current flowers though a conductor is directly proportional to the Potential Difference across it .
V=RI [R=constant of proportionality called Resistance]
Diagram
OR
27. (a) What is a conductor of electricity? Give two examples.
(b) Why is series arrangements not used in domestic circuits?
Answer:
(a) Conductor: Those materials which conduct or allow the electricity to pass thought them are known as conductors.
Example: copper
Gold
Silver
Aluminium
(B) (i) In series if one electrical appliance stop working them all other also stopped.
(ii) In series all appliances have one switch due to which they cannot be turn on/of separately.
(iii) In series all appliances do not get same voltage.
28. Write three physicsal properties and twochemical properties of metals.
Answer:
Physical properties of Metals:
(i) Malleability : The metals can be converted into thin sheets by hammering example:- Aluminium, Gold etc.
(ii) Ductile : The metals can be converted into wires by stretching.
Example:- Copper, Silver etc.
(iii) Heat and Electricity: Metals are good conductors of heat and electricity
Example:- Silver, Copper etc.
Chemical properties of metals:
(i) Metals react with oxygen and form metal oxide.
Na+O2→Na2O
K+O2→K2O
(ii) Most of metal oxide are insoluble in water .but some of metal oxides dissolved I water to from Alkalis (base)
(iii) Aluminium is the metals which react with oxygen on strong heating
OR
28. (a) Write three methods to prevent rusting of iron.
(b) Give example of a non-metal which is
(i) Good conductor of electricity
(ii) has lustre.
Answer:
(a) (i) By painting the object
(ii) By galvanization
(iii) By tin plating or Chromium plating.
(iv) By applying grease or oil.
(b) (i) Graphite
(ii) Iodine