Marvel Science Question paper set 3

Marvel Science board question paper set No.3 
                 
               

                          Section-A
Answer the followig Q. No. 1 to 18 (within the limit of 10 to 20 words) as directed:
(1 mark each)
Fill in the blanks so as to make each of the following statements true :
1. Reduction is the  loss of oxygen or gain of hydrogen.
2. The ratio V/I is called Resistance
3. Central nervous system is consist of Brain and Spinal cord
4. The cells in human female have chromosomes of the type 44 + XX
State whether the following statement are true or false.
5. ADH helps in reabsorption of water from nephron. TRUE
6. Detergents give scum with hard water. FALSE
7. The polar end in soap is called hydrophilic end .TRUE
Choose the correct option and write it with answer from those given below multiple
choice questions : (MCQs)
8. The most rapidly dwindling natural resource in the world is
(a) Water
(6) Forests
(c) Wind
(d) Sunlight
9.An ecosystem includes
(a) all living organisms
(b) non-living objects
(c) both living organisms and non-living objects
(d) sometimes living organisms and sometimes non-living objects
10. Which of the following is a non-renewable source of energy?
(a) Wood all
(b) Sun
(c) Fossil fuels
(d) Wind
11. Select the incorrect statement
(a) Frequency of certain genes in a population change over several generations resulting
in evolution.
(b) Reduction in weight of the organism due to starvation is genetically controlled.
(c) Low weight parents can have heavy weight progeny.
(d) Traits which are not inherited over generations do not cause evolution.
Answer the following questions as directed :
12. Name the transparent membrane through which light enters the eye.Cornea
 Write the name and symbol of the element from the description.
13.The most electronegative atom.Fluorine
Write the name and symbol of the element from the description.
14.The noble gas with thesmallest atomic radius.Helium
15.Define: Power of lens.
Reciprocal of the focal length of a lens
16. What is the full form of AIDS?
Acquired immunodeficiency syndrome

Section : B

Answer the following questions Q. no. 17 to 24
directed : (2 marks each)
17. Explain the action of dilute HCL on the following, with
a. Magnesium ribbon
b. Sodium hydroxide
c. Crushed egg shells
✴Reaction of hydrochloric acid with magnesium ribbon.
In this reaction hydrochloric acid react with magnesium ribbon and form magnesium chloride and hydrogen gas.
2HCl+ Mg =========》 MgCl2 +H2
✴Reaction of hydrochloric acid with sodium hydroxide.
HCl+ NaOH ========》NaCl + H2O
that is when hydrochloric acid react with Sodium Hydroxide it leads to the formation of the salt sodium chloride and water.
✴Reaction with crushed egg cell.
2HCl+ CaCO3 ========》CaCl2 + CO2 + H2O
when hydrochloric acid reacts with crushed egg shells and utilise to you formation of calcium chloride carbon dioxide gas and
18. Diffrentiate between metals and no metals on the basis of their chemical reaction
Chemical properties of metal:-
#Reaction with oxygen
Metals reacts with oxygen to form metal oxide.
#Reaction with water
When metal react with water it forms metal hydroxide or oxide.
#Reaction with dilute acid
Metals reacts with diluted acid to form metals salt and hydrogen gas.
#Reaction of metal with salt of other metal
When metal reacts with salt sol. of other less reactive metal it displaces it from salt sol. and separate it out.
#Reaction with hydrogen
Generally metals do not combines with hydrogen but fer more reactive metal like sodium , potassium , calcium and magnesium combines with hydrogen and forms metal hydride.
Chemical properties of non metals:-
#Reaction with oxygen
Non metals reacts with oxygen to form non metallic oxide.
#Reaction of non metal with water
There is no reaction b/w non metals and water.
#Reaction with dilute acide
There is non reaction b/w non metals and dilute acide.
#Reaction of non metal with other non metallic salt
During this reaction a more reactive non metal displaces less reactive non metal from its salt sol.
#Reaction of non metal with chlorine
Non metals reacts with chlorine to form non metallic chloride.
#Reaction with hydrogen
Non metal reacts with hydrogen to form an nonmetallic hydrogen
19. How does the electronic configuration of an atom relate to its position in the Modern Periodic Table?
The electronic configuration of an atom relates to its position in the modern periodic table as when we arrange the electrons in the 1st , 2nd , 3rd and 4th shells i.e. ... So, its' electronic configuration is 2,8,1 and its valency is +1 . This element therefore comes in Group 1 with +1 valency.To know its position in periodic table first we should know the electronic configuration of the element. Valence electrons: The electrons, which are present in the outermost shell of an atom are called valence electrons. ... For any element the valence shell number is equal to its period number.
OR
19. How could the Modern Periodic Table remove various anomalies on mendeleev's periodic Table ?
The Modern Periodic Table could remove various anomalies of Mendeleev's Periodic Table: a) In the Modern Periodic table elements are arranged in the increasing order of their atomic number, removing the anomaly regarding certain pairs of elements in Mendeleev's periodic table.
20. What is the role of saliva in the digestion of food?
Saliva contains an enzyme called salivary amylase ....which helps to break down sugar into more simpler form that is starch..
OR
20. Draw a well-labelled diagram of human excretory system.

21. Draw the labelled diagram of
a. germination of pollen on stigma.
b. seed germination.
c. structure of seed.

22.Explain Refraction by spherical lenses.
Refraction is the change in direction of light when it passes from one medium to another. The working of a lens is based on therefraction of light when they pass through it.Lens is a transparent glass which is bounded by two spherical surfaces. The light rays arerefracted after passing through the lens.
23. State Ohm's law and write its formula.
Ohm's Law Formula Voltage= Current× Resistance. V= I×R. V= voltage, I= current and R= resistance. The SI unit of resistance is ohms and is denoted by Ω This law is one of the most basic laws of electricity
Ohm's law states that the electrical current (I) flowing in an circuit is proportional to the voltage (V) and inversely proportional to the resistance (R). Therefore, if the voltage is increased, the current will increase provided the resistance of the circuit does not change.
OR
23.Write the disadvantages of series connection ?
in a series connection if one device is damaged then it also affects the other electrical appliances
series connection is not safe for house hold purpose
24.State right hand thumb rule
Right hand thumb rule was given by Maxwell. So this rule is also known as Maxwell’s right hand thumb rule. According to this rule, imagine that you are holding a current carrying wire in your right hand so that the thumb points in the direction of the current, then the direction in which the fingers wrap the wire will represent the direction of magnetic lines of force.
25.What is the significance of food chain? 
 Food chain helps in studying feeding relationships between organisms. *Food chain also helps us to know how much energy we gain by consuming which food. *Food chain helps us to know energy flow from one trophic level to another trophic level
26.Why should we conserve wild life and forest?
We should conserve forests and wildlife because they are essential for us in following terms:
→ Forest provide us oxygen, they cause rain fall.
→ Forest prevents soil erosion.
→ Plants are dependent on animals and birds for their pollination and seed dispersal.
→ Forests provide us various medicines.
→ Various forest products are used as raw materials in industries.
26.Why are some forest known as biodiversity hot spot?
A biodiversity hotspot is a region of the Earth that is extremely biologically diverse and also under severe threat due to habitat loss, climate change, or extensive species loss. ... Forest serves as the reservoir of biodiversity containing different species of plants, animals and all other sorts of living organisms.
Section-C
Answer the followig Q. No. 27 to 34 (within the limit of 80 to 60 words) as directed: (3 mark each)
27.Explain the effects of oxidation reaction in everyday life
1.Combustion is the most common example for oxidation reactions.
2.Rising of dough with yeast depends on oxidation of sugars to carbon dioxide and water.
3.Bleaching of coloured objects using moist chlorine.
4.Coloured object + (O) ------> Colourless object (Here ‘O’ is known as Nascent
oxygen)
Sometimes during rainy season the power supply to our homes from the electric pole will be interrupted due to formation of metal oxide layer on the electric wire. This metal oxide is an electrical insulator. On removing the metal oxide layer formed on the wire with a sand paper, supply of electricity can be restored.
28.To show that metals are good conductors of heat
a) A metal is a good conductor of electricity as well as heat. To experimentally show it, we can take a metallic rod and heat with fire on one side of the rod, gradually the other side of the rod starts get heating up, this is how the conductivity of the metals can be shown.
b) Mercury is extracted from its ore by heating the ore in a flow of air and then the mercury is condensed.
28.To illustrate the reaction of metals with salt solution.
When more reactive metal react with solution of less reactive metal salt, more reactive metal displace less reactive metal from its salt.
M1 + M2B(aq) → M1B(aq) + M2
Where M1 is more reactive metal than M2 and M2B is salt of metal M2.
Such reaction is known as displacement reaction or single displacement reaction.
Example:
Reaction of Iron with solution of copper sulphate
When iron nail reacts with the solution of copper sulphate, iron displaces copper and forms iron sulphate.
reaction of iron with the solution of copper sulphate reaction of iron with the solution of copper sulphate1
In this reaction iron is more reactive than copper.
Reaction of zinc with solution of copper sulphate
When zinc reacts with the solution of copper sulphate, zinc sulphate and copper metal is formed.
 reaction of zinc with the solution of copper sulphate  reaction of zinc metal with the solution of copper sulphate1
In this reaction, zinc is more reactive than copper, thus zinc displaces copper from copper sulphate.
Reaction of copper with solution of silver nitrate
When copper reacts with the solution of silver nitrate, copper displaces silver from the solution of silver nitrate and copper nitrate is formed.
reaction of copper metal with the solution of silver nitrate  reaction of copper metal with the solution of silver nitrate1
In this reaction copper is more reactive than silver
Reaction of silver with solution of copper sulphate
When silver metal is kept dipped in the solution of copper sulphate, no reaction takes place.
Silver metal + copper sulphate solution → No reaction
This happens because silver is less reactive than copper and does not displaces copper from the solution of copper sulphate.
Thus, less reactive metal do not displace more reactive metal from its salt solution.


29.What is reflex action Give two examples. Explain the function of any two of its parts
A reflex action is defined as a spontaneous, automatic and mechanical response to a stimuli without the will of an individual. In such actions there is no involvement of the brain. All reflex actions are conveyed through the spinal cord by a path called reflex arc.
The reflex action travels in the following sequence:

The reflex arc constitutes the following components:
A receptor to perceive the stimulus.
A sensory or afferent nerve which carries the message from the receptor to the spinal cord.
The neurons of spinal cord transmit the impulse from afferent neurons to efferent neurons.
The motor or efferent nerve carries messages from spinal cord to the muscles (effectors) that show the response.
Some examples of reflex actions are:
Blinking of eyes when a foreign particle gets in them.Sneezing if an unwanted particle enters the nose.Watering of mouth at the sight or smell of good food.Withdrawal of foot while walking if a nail comes in the way and pricks the foot.Immediate withdrawal of hand of a person if some hot thing touches it.
30.Distinguished between self and cross pollination.
Self-Pollination Cross-Pollination
Transfer pollen grains from the anther to the stigma of the same flower.
This process can take place either in the same flower or another flower of the same plant.
It occurs in the flowers which are genetically same.
Occurs only in perfect flowers.
Causes homogenous conditions in progenies.
Self-pollination increases genetic uniformity and decreases genetic variation.
Causes inbreeding.
Reduces the gene pool.
Produces limited amounts of pollen grains.
In self-pollination, both the stigma and anther mature at the same time.
Transfers few numbers of pollen.
This process is carried out even when the flowers are closed.
No need of pollinators to transfer pollen grains.
Pollen grains are directly transferred onto the stigma of the flower.
This process can take place between two flowers on different plants.
It occurs between flowers which are genetically different.
Occurs both in perfect or imperfect flowers.
Causes heterozygous condition in progenies.
Cross-pollination decreases genetic uniformity and increases genetic variation.
Causes outbreeding.
Maintains the gene pool.
Produces large amounts of pollen grains.
In cross-pollination, both the stigma and anther mature at the different time.
Transfers large numbers of pollen.
For cross-pollination to happens flower should be open.
Require pollinators to transfer pollen grains.
Pollen grains are transferred through insects, wind, water, animals, etc
Transfer pollen grains from the anther to the stigma of the different flower.
31.List three factors that provide evidance in favour of evolution and state role of each in brief
Three factors that provide evidences are:
Analogous organs: organisms with similar looking organs may have different origin.
Homologous organs : organisms with apparently different looking organs may have similar origin.
Fossils: allow us to make estimates of how far back evolutionary relationships go. Fossils when chronologically arranged help in tracing the evolutionary history of an organism
32.Write a brief note on evolution of human
There is a great diversity of human forms and features across the planet. Skin color are used to be the commonest way of identifying the so called-races. But all humans or homo sapiens are a single species. We all humans have came from Africa. A couple of years ago, some of our ancestors left Africa and migrated to West Asia, Central Asia, Eurasia, South Asia and East Asia. Like all other species on the planet, they had come into being as an accident of evolution while trying to live their lives the best they could
OR
32 Sign conventions for spherical mirrors.
Sign convention for reflection by spherical mirrors
Reflection of light by spherical mirrors follow a set of sign conventions called the New Cartesian Sign Convention. In this convention, the pole (P) of the mirror is taken as the origin. The principal axis of the mirror is taken as the x-axis (X�X) of the coordinate system. The conventions are as follows �
The object is always placed to the left of the mirror. This implies that the light from the object falls on the mirror from the left-hand side.
All distances parallel to the principal axis are measured from the pole of the mirror.
All the distances measured to the right of the origin (along + x-axis) are taken as positive while those measured to the left of the origin (along � x-axis) are taken as negative.

Distances measured perpendicular to and above the principal axis (along + y-axis) are taken as positive.
Distances measured perpendicular to and below the principal axis (along �y-axis) are taken as negative.
These new Cartesian sign convention for spherical mirrors are shown below in the figure Sign convention for reflection by spherical mirrors
33.Explain resiatance of a system of resistors.
many resistors are used in combination. For example; the wiring of a room may contain various resistors in different combinations. In this section, you will read about different possible combinations of resistors.

Resistors are combined in two types of combination, viz. series combination and parallel combination. The following figure shows the series combination of resistors. In this circuit, R1, R2 and R3 are the three resistors which are in series combination. When resistors are connected end to end, i.e. one terminal of one resistor is connected to the terminal of the next resistor and so on, this is called series combination.

The following figure shows the parallel combination of resistors. In this circuit, R1, R2 and R3 are the three resistors which are in parallel combination. When one terminal of all resistors are connected together and another terminal is also connected in the same way, it is called parallel combination.



Resistors in Series

Let us do the following actions to know what happens to total resistance or to current when many resistors are connected in series.
34.Explain construction and working of a bio-gas plant with a labeled diagram.
Biogas is produced using organic mateeye. is broken down with the help of bacteria in an anaerobic (oxygenure. In a biogas plant, this process takes place in an anaerobic digester and is accelerated by creating the best possible conditions for micro-organisms and bacteria to multiply, which leads to a highly efficient breakdown of materials.

Almost all forms of organic material can be used to produce biogas. However, waste water, manure, energy crops and organic industrial waste are the most common feedstocks.

                          Section : D
Answer the following Q. no. 35 to 39 in detail (within the limit of 90 to 120 words)
rected : (4 marks each)
35.Draw and expain structure of nephrons. Expain Function of nephrons.

Answers =Nephron is the microscopic structural and functional unit of the kidney. It is composed of a renal corpuscle and a renal tubule. The renal corpuscle consists of a tuft of capillaries called a glomerulus and an encompassing Bowman's capsule. The renal tubule extends from the capsule. The capsule and tubule are connected and are composed of epithelial cells with a lumen. A healthy adult has 0.8 to 1.5 million nephrons in each kidney.   The nephron uses four mechanisms to convert blood into urine: filtration, reabsorption, secretion, and excretion of numerous substances. The structure and function of the epithelial cells lining the lumen change during the course of the nephron, and have segments named by their location and which reflects their different functions.
☆ STRUCTURE OF NEPHRON:-♤ Each nephron is a long - coiled tubule whose one end is cup - shaped called Bowman's capsule while other ends are connected to urine collecting duct of the kidney.
♤ The Bowman's capsule contains a bundle of blood capillaries which is called glomerulus.
☆ FUNCTION OF NEPHRON:-♤ It is the functional unit of kidney.It filters the uncleaned blood so that waste substances can be removed from the blood.
36.State the rule to determine the direction of
a) magnetic field produced around a straight current carrying conductor,
b) force experienced by a current-carrying straight conductor placed in a
field which is perpendicular to it, and
c) current induced in a coil due to its rotation in a magnetic field.
:-Fleming's right hand rule -When we hold the three fingers : thumh, pointer and middle finger of our right hand in such a way that all the three fingers are mutually perpendicular to each other and the thumb shows the direction of force exerted on the conductor, and the index finger shows the direction of magnetic field then the middle finger finger will give us the direction of induced current.
37.What is triple bond or triple covalent bond? Explain the formation of triple bond giving
two examples.
The bond formed between two atoms through the sharing of three electron pairs is called a triple bond. Three horizontal lines between two atoms denote a triple bond, e.g., nitrogen molecule is given asN≡N.

(i) Formation of N2 molecule: Nitrogen atoms have five electrons in their outermost shells. Therefore, in N2 molecules, two nitrogen atoms share 3 electrons with each other, thus acquiring the stable structure and forming a N2 molecule with triple bonds.

(ii) Formation of acetylene molecule (C2H2): In acetylene molecule, each carbon atom satisfies its valency by sharing one electron with a hydrogen atom and sharing the other three electrons with the other carbon atom as shown:

38.To show that acid reacts with metal carbonate to liberate carbon dioxide.
Aim : To show that all metal carbonates and hydrogen carbonates react with acids to give a corresponding salt.
Required Materials :Two test tubes,Sodium carbonate,Sodium hydrogen carbonate,Two holed rubber stopper,Thistle funnel,Stand,Dilute hydrochloric acid,Delivery tube,Calcium carbonate (in a test tube)

Procedure :Take a test tube A with 0.5 gm of sodium carbonate.
Close the test tube A with two holed rubber stopper.
Insert a thistle funnel through one hole and insert a delivery tube through the other hole.
Pour 2ml of dilute HCl to the test tube A.
Do the same as above with test tube B with sodium hydrogen carbonate. Observation : Carbon dioxide is released from test tube A and B.

Result: All metal carbonates and hydrogen carbonates react with acids to give a corresponding salt.
OR
38.To show that crystals of salts contain water of crystallization.
Activity to demonstrate water of crystallization :
Take a few crystals of hydrated copper sulphate in a dry test tube and heat the test tube.

We observe water droplets on the walls of the test tube.
The blue colour of copper sulphate crystals is lost and the substance has be-come white. .
Add 2 or 3 drops of water on the sample of copper sulphate obtained after heating.
The blue colour of copper sulphate is restored.
In the above activity copper sulphate crystals which seem to be dry contain the water of crystallization and when these crystals are heated the water present in crystals is evaporated and the salt turns white.
Water of crystallisation is the fixed number of water molecules present in one formula unit of a salt.
39.To find out a pattern of concentric circles indicating the field lines of a magnetic field
around a straight conducting wire.
:- Magnetic Field around a straight wire current carrying conductor will be concentric circles.
1)Rule that is used to find the direction of magnetic  filed is Right Hand thumb rule . which states that " If you hold a current carrying conductor in our hand , if thumb indicates the direction of current then four fingers curled direction will be the direction of magnetic field."
Please see the attachment for the diagram.
2)Yes similar magnetic field will be observed around a thin beam of moving
(α) alpha particles  as they are positively charged particles.
3) Neutrons will not produce any pattern of magnetic field as they do not have charge
Please mark me as brainlist