SCIENCE QUESTIONS FOR THE PREPARATIONS OF SA-1/SA-2, CBSE BOARD
CLASS
–X(THREE MARKS)
Q1 On heating green coloured
crystals, a gas with a characteristic odour of burning sulphur evolves and the
colour of crystals change.
(i)
Name the gas evolved with its
chemical formula.
(ii)
Identify the green crystals.
Q2 Name the type of chemical reaction taking
place. “Combination reaction is the reverse of decomposition reaction”. Justify
this statement with the help of appropriate chemical equation for each.
Q3 Naman and Raghav perform an
experiment in which they mix concentrated sulphuric acid with water. Naman
mixes water to acid and Raghav mixes acid to water slowly with constant
stirring. Mention the suitable reason for selecting the one which you find is a
correct method and discarding the one which is wrong.
(a) Compare the properties of a typical metal
and a non- metal on the basis of the following : (i) Nature of the oxide formed
by them (ii) Conductivity
(b) Name a non - metal which is lustrous and a
metal which is liquid at the room temperature.
IX and X class CBSE maths sylabus
IX and X class CBSE maths sylabus
Q4 Find
the equivalent resistance across the two ends A and B of this circuit .
Resistivity of two elements A and B
are 1.62 x 10-8Ώm and
520 x 10 -8Ώm
respectively. Out of these two, name the
element that can be used to make (i) filament of electric bulb. (ii) wires for
electrical transmission lines. Justify your answer in each case.
Q5 Write one difference between direct current
and alternating current. Which one of the two is mostly produced at power
stations in our country. Name one device which provides alternating current.
State one important advantage of using alternating current.
Q6.(a) A product is formed in our
muscles due to break down of glucose when there is a lack of oxygen. Name the
product and also mention the effect of build up of this product. (b) Differentiate
between fermentation in yeast and aerobic respiration on the basis of end
products formed.
Q7 Mention one role of each of the
following : (i) Cerebellum (ii) Fore - brain (iii) Medulla
Q8 Name the hormone that is secreted by our
body to deal with scary situations. List any two responses shown by our body
when this hormones is secreted into the blood.
Q9 List three energy sources that are
considered to be inexhaustible. State three reasons in support of your answer.
Q10.Increasing demand of fossil fuels has
caused harm to our environment. List its three ill - effects. Suggest three
measures to reduce the consumption of fossil fuels.
Q11Three test tubes A, B, and C are taken with
the contents shown in the following figure.
(i) State the points of observations
in each test tube after a few days. (ii) Suggest the suitable reasons for each
observation. (iii) Report the conclusion after this activity is performed.
Q12 Zinc is the metal which lies in the middle
of the activity series. This metal is extracted from its sulphide ore.
(i)
Outline the steps involved in the
process of extraction of zinc metal with the help of balanced chemical equation
for each step.
(ii)
Name the reducing agent commonly used during
the process.
(iii)
Name the method used for refining the impure
zinc obtained after reduction.
Q13 A reddish brown coloured metal,
used in electrical wires, when powdered and heated strongly in an open china
dish, its colour turns black. When hydrogen gas is passed over this black
substance, it regains its original colour. Based on the above information
answer the following questions.
(i)
Name the metal and the black coloured
substance formed.
(ii)
Write balanced chemical equations for both the
reactions. (a) Give an example for a combination reaction which is exothermic.
(b) Identify the oxidising and reducing agent.H2S
+ Cl2 → 2HCl +S
(c)
Name the phenomenon due to which the taste and smell of oily food changes when
kept for a long time in open. Suggest one method to prevent it.
Q15.(a) Write the name given to bases
that are highly soluble in water ? Give an example.
(b) How is tooth decay related to pH
? How can it be prevented ?
(c) Why does bee sting cause pain and
irritation ? Rubbing of baking soda on the sting area gives relief. How ?
Q16.(a) Why is calcium starts
floating when added to water ?
(b) Most of the metals do not give
hydrogen while reacting with nitric acid. Why ?
(c) Write equation for the reaction
of iron with steam. Name the compound of iron obtained. .
Q17 (a) Nichrome wire of length l and
radius ‘r’ has resistance of 10Ώ, How would the resistance of the wire changes.
when : (i) Only length of the wire is doubled ? (ii) Only diameter of
the wire is doubled ? Justify your answer. (b) Why element of electrical
heating devices are made up of alloys ?
Q18Three resistors of 5Ώ,10Ώ and 15Ώ are
connected in series and the combination is connected to battery Ammeter and voltmeter are connected in the
circuit. Draw a circuit diagram to connect all the devices in proper correct
order ? What is the current flowing and potential difference across 10 Ώ
resistance ?
Q19.What is meant by overloading of an
electrical circuit ? Explain two possible causes due to which overloading may
occur in household circuit ? Explain one precaution that should be taken to
avoid the overloading of domestic electric circuit.
Q20.(a) Explain with the help of diagram, how
amoeba takes its nutrition.
(b) Assume that you are a veterinary
surgeon and you had removed a good length of the small intestine of a bear that
was suffering from a intestinal tumor. Now, would you suggest a plant based or
an meat based diet for the bear after its recovery ? Give reason for your
answer.
Q21(a) Name the part of brain which controls
(i) voluntary action, (ii) involuntary action.
(b) What is the significance of the
peripheral nervous system ? Name the components of this nervous system and
distinguish between the origin of the two.
Q22 Describe an activity to
illustrate the phenomenon of phototropism and explain why does this occur.
Q23 Draw schematic labeled diagram of box type
solar cooker. Name two components of solar cooker which are responsible to
increase the temperature inside the solar cooker. Explain their function.
Q24 Explain geothermal energy. How can it be
harnessed to produce electrical energy ?
Q25The following diagram displays a
chemical reaction. Observe carefully and answer the following questions :
(a) Identify the type of chemical reaction
that will take place and define it. How will the colour of the salt change.
(b) Write the chemical equation of the
reaction that takes place.
(c) Mention one commercial use of
this salt.
Q26. (i) Why is respiration
considered as an exothermic reaction ?
(ii)Write chemical name and the
formula of the brown gas produced during thermal decomposition of lead nitrate.
(iii)Why do chips manufacturers flush
bags of chips with gas such as nitrogen ?
Q27. What is a reduction reaction ?
Identify the substances that are oxidised and the substances that are reduced
in the following reaction. (i) Fe2O3 + 2Al → Al2O3
+ 2Fe (ii) 2PbO + C → 2Pb + CO2
Q51. Write the names of the products
formed when zinc reacts with NaOH. Also write the balanced chemical equation
for the reaction involved. Write a test to confirm the presence of the gas
evolved during this reaction.
Q28. (a) Why does calcium start
floating when it reacts with water ? Write the balanced chemical equation of
the reaction. (b) Name two metals which do not react with water.
Q29. A copper wire has diameter 0.5
mm and resistivity 1.6 x 10-8Ώm. Calculate the length of this wire
to make its resistance 10Ώ . How much
does the resistance change if the diameter is doubled without changing its
length ?
Q30. (a) Why is tungsten used for
making bulb filaments of incandescent lamps.
(b) Name any two electric devices
based on heating effect of electric current.
(c) An electric bulb is connected to
a 220V generator. The current is 2.5 A. Calculate the power of the bulb.
Q31. (a) State Right Hand Thumb rule
to find the direction of the magnetic field around a current carrying straight
conductor.
(b) How will the magnetic field be
affected on : (i) increasing the current through the conductor (ii) reversing
the direction of flow of current in the conductor.
Q32. Explain with the help of neat
and well labelled diagrams the different steps involved in nutrition in Amoeba.
Q33 (a) Draw a neat diagram of a neuron and
label (i) dendrite and (ii) axon
(b) Which part of the human brain is
: (i) the main thinking part of the brain ? (ii) responsible for maintaining
the posture and balance of the body ?
Q34. Nuclear power is an excellent
non – conventional source of energy. Still it is not used commonly for power
generation. Why ? State three reasons.
Q35. State the main difference between thermal
power and hydro power plants based on electricity generation. Name two dams/projects
which were opposed due to the problems of rehabilitation of displaced people,
damage to the ecosystem etc.
Q36. (a) Identify the substances that
are oxidized and the substances that are reduced in the following reactions :
(i)
Fe2O3 + 2Al →Al2O3
+ 2Fe
(ii) 2 PbO + C → 2Pb + CO2
(b) What is meant by redox reaction?
Q37 State reasons for the following :
(a) Iron articles get coated with a
reddish brown powder when left for sometime in open.
(b) Burning of coal is an exothermic
reaction.
(c) The chemical equations should be
balanced.
Q38. (a) State one example of a
synthetic indicator and an olfactory indicator ?
(b) How do bacteria decay our teeth ?
Why do we basic tooth pastes for cleaning our teeth ?
Q39. (a) Why do ionic compounds have
high melting and boiling points ?
(b) Show the formation of sodium
chloride (NaCl) by the transfer of electrons (atomic number – Na – 11, Cl – 17).
Q40. A hot plate of an electric oven,
connected to a 220 V line. It has two resistance coils A and B each of 30Ώ
resistance which may be used separately, in series or in parallel. Find the
value of the current required in each of the three cases.
Q41. State reasons for the following
: (a) Tungsten is used for making bulb filaments .
(b) Copper and aluminium are
generally used for electricity transmission.
(c) Alloys are commonly used in
electrical heating devices such as electric iron and toaster.
Q42. State one main difference
between A.C and D.C. Why A.C is preferred over D.C for long range transmission
of electric power ? Name one source each of D.C and A.C.
Q43. List two functions of stomata.
Name the cells which control the opening and closing of stomata. How do they
perform this function ?
Q44. (a) Name the plant hormone which
is present in greater concentration in areas of rapid cell division. (b) How is
pea plant able to climb up other plants or fences ? Explain.
Q45. Draw a neat diagram of a neuron.
Label the following parts and state one function of each : (a) dendrite (b)
axon
Q46. Name the process through which nuclear
energy is generated. State two examples of elements which are used for nuclear
energy generation. List any two reasons which make large scale use of nuclear
energy prohibitive.
Q47. Identify the substances that are
oxidised and the substance that are reduced in the following reactions
(i)
Zn O + C→ Zn +CO
(ii)
4 Na + O2→ 2 Na2O
(iii)
Cu O +
H2→ Cu + H2O
Q48. Write the chemical name and
formula of washing soda. How is it prepared ? Write balanced chemical equation
of the reaction.
Q49. Define the term alloy. When is
it known as an amalgam ? Write the constituents of the alloy, brass.
Q50. (i) the value of current through
each resistor. (ii) the total current drawn from the battery. (iii) the total
effective resistance of the circuit.
Q51. Give reasons for the following :- (i)
Household appliances are connected in parallel (ii) Alloys instead of pure
metals are used in making heating elements of heating devices. (iii) Aluminium
and copper are used for making wires for long distance transmission of power.
Q52. (i) What is an electromagnet (ii) Name
the material which can be used to make – (a) Permanent magnet (b) Temporary
magnet. (iii) State two ways by which the strength of an electromagnet can be
increased.
Q53. What will happen if: (i) Mucus
is not secreted by the gastric gland. (ii) Leaves of plants are covered with
Vaseline. (iii) Bile is not produced in liver.
Q54. An endocrine gland ‘P’ is
located below the stomach in the human body. The gland P secrets a hormone H.
the deficiency of hormone H in the body leads to rise in blood sugar due to
which a disease D is caused. (i) Name the gland P and the hormone H. (ii) State
the functions of hormone H. (iii) Name the disease D. (iv) Suggest two
precautions to be taken by the person who is suffering from the disease D.
Q55. With the help of a labelled
diagram illustrate the pathway of response when someone pricks in your hand
with pin
Q56. (i) Why is hydrogen considered a
better and cleaner fuel than CNG ? (ii) Mention any two areas where solar cells
are used as source of energy. (iii) State the biggest hindrance in trapping
geothermal energy
Q57. (a) Why is concave mirror used
in some solar cookers in place of a plane mirror ? (b) Mention any two factors
which affect the cooking time of a solar cooker ? (c) State a limitation of
using solar cooker. Q58. (i) State the colour of ferrous sulphate crystals
before heating and after heating (ii) Mention the smell of the gases evolved when
ferrous sulphate crystals are further heated. (iii) Write the balanced chemical
equation for the reaction. What kind of reaction does it represent?
Q59. (i) Why is respiration
considered an exothermic process? (ii) A shiny brown colored element ‘X’ on
heating in air becomes black in colour. Name the element X and the black
colored compound formed. Give a chemical equation for this reaction.
Q60. Give reasons: (i) Copper vessels develop
a green coating when exposed in air. (ii) Acids like HCl and HNO3
show acidic characters in aqueous solutions while solutions of compound like
alcohol and glucose do not show acidic character. (iii) Dry HCl gas does not
change the colour of the dry litmus paper.
Q61. Define the term “alloy” and
‘amalgam’. Name the alloy used for welding electric wires together and state
its constituents.
Q62. Find the total resistance between the
points A and B in the circuit diagram shown.
Q63. Study the circuit as shown below.
A current of 0.6 A shows in the circuit when
the key K2 is closed. Find the resistance of the lamp L. Now if the key K2 is
also closed, what change in current flowing through the 5 Ω conductor and
potential difference across the lamp will take place. State reason for your
answer .
Q64. What happens if a domestic
electric circuit is short circuited? An electric iron of rating 1000w; 220v is
to be operated in a 220V electric circuit in which an electric fuse of 3A
rating is connected. What is likely to happen when the electric iron operates?
Justify your answer.
Q65. State the three common features
of respiratory organs of animals
Q65. (a) What is the pathway of reflex arc?
(b) Answer the following: (i) Which hormone is responsible for the changes
noticed in females at puberty? (ii) Deficiency of which hormone is responsible
for the rise of blood sugar level? (c) Draw diagram of neuromuscular junction.
Q66. Describe an experiment to
demonstrate hydrotropism.
Q67. Describe the process of biogas
production in a biogas plant.
Q68. Mention three advantages and
three disadvantages of producing hydro electricity by building dams on rivers.
Q69. (a) A solution of a substance
‘X’ is used for testing carbon dioxide. What will be the reaction of ‘X’ with
carbon dioxide? Write balanced equation for this reaction. (b) How is ‘X’
obtained? Give chemical equation.
Q70. Describe an activity to prove that all
hydrogen containing compounds such as alcohols and glucose are not acids.
Q71. (a) Show the formation of NaCl from
sodium (At No. 11) and chlorine (At No. 17) atoms by the transfer of electrons.
(b) Why does sodium chloride have a high melting point ?
Study the following circuit and answer the questions that follow:
(a) State
the type of combination of the two resistors in the circuit.
(b) How much current is
flowing through (i) 10 Ω and 15Ω resistors.
(c) What is the ammeter reading ? .
Q73. Resistance of a metal wire of
length 25 cm is 6.5Ω, If the diameter of the wire is 0.3 mm. calculate the
resistivity of metallic wire.
Q74 What potential difference is
maintained between the live wire and the neutral wire in our domestic electric
supply ? The main power supply of a house is through a 5 A fuse. How many 100 W
bulbs can be used in this house at the correct voltage ?
Q75. An experiment was performed to
demonstrate that chlorophyll is essential for photosynthesis. Given below are
the diagrams of a variegated leaf before and after starch test: (a) What would
be the colour of the areas ‘A’ and ‘B’? (b) During the experiment, why is the
leaf dipped in alcohol? (c) Why the plant from which leaf is taken was kept in
the dark for 2-3 days ?
Q76. Name the two main organs of our central
nervous system. Which one of the two plays a major role in sending command to
muscles to act without involving thinking process? Name the phenomenon
involved. Name the receptors which detect (i) taste (ii) smell
Q77 (a) Draw a diagram of human brain
and label on it cerebrum and cerebellum. (b) State the role of cerebellum.
Q78. With the help of a diagram, state the
construction and working of a box type solar cooker. Q106. What is a wind
energy farm? State its importance with two limitations.
Q79. Name the substance oxidized and the
substance reduced in each of the following reactions : 3CO2 13CO → 2Fe 1(i) Fe2O3 H2O 1SO2 → S 12Al2O3 (iii) H2S 14Al → 3Mn 1(ii) 3MnO2 Q108. Look at the
figure given below and answer the following questions (i) Out of the two test
tubes A and B state the tube that contains hydrogen gas. (ii) If the volume of
hydrogen gas collected is 10 mL, what will be the volume of oxygen collected ?
(iii) State the purpose of adding a few drops of dil. sulphuric acid to the
water in plastic mug.
Q80. (a) Write the chemical formula
for washing soda. How may it be obtained from baking soda ? Write an industrial
use of washing soda other than washing clothes. (b) How will you test the gas
which is liberated when hydrochloric acid reacts with an active metal ?
Q81 (a) Show the formation of Na2O by
transfer of electrons between the combining atoms. (b) Why are ionic compounds
usually hard solids ? (c) Why do ionic compounds conduct electricity only in
molten state but not in solid state ?
Q82. Two room heaters rated 220 V; 500 W and
220 V; 800 W are used in a house hold. If these heaters are connected in
parallel to 220 V mains supply, calculate : (i) the current drawn by each
heater (ii) total electric energy consumed in commercial units if they operate simultaneously
for 2 hours.
Q83. (a) What is meant by „electric
resistance‟ of a conductor ? (b) A wire of length „l‟ and resistance R is
stretched so that it length is doubled and the area of cross section is halved.
How will its : (i) resistance change ? (ii) resistivity change ?
Q84 What is „short circuiting ? Electric
supply of a house is through a 15 A fuse. When a 2000 W heater is used in this
house, how many 100 W bulbs can be used simultaneously ? The supply is at 220
V, and the heater and the bulbs are rated for 220 V.
Q85 Complete the glucose break down pathway in
case of aerobic respiration by filling the blanks : Q86. What is phototropism ?
State its cause. Describe an activity to demonstrate it.
Q87. What are receptors with
reference to nervous system ? List three types of receptors and mention their
function. How do receptors pass the information to brain ?
Q88. What is a solar panel ? List its
three technological applications. Why is domestic use of these cells limited ?
Q89. List three main hazards of
nuclear power generation. Q119. Define the property of catenation of carbon.
Q90. A person can read a book clearly
but cannot see distant objects distinctly. Name the defect of vision he is
suffering from.
Q91. (a) Write chemical names of CH3COCH3,
C2H5COOH. (b) What happens when acetic acid and methanol react in presence of
concentrated H2SO4 ? Write the reaction there in.
Q92. Given below is a part of the
periodic table. As we move horizontally from left to right :- (a) what happens
to the atomic size? Justify your answer. (b) what happens to the metallic
character of the elements ?
Q93. (a) What are sexually
transmitted diseases? Name any one which is caused by bacteria and one by viral
infection. (b) Mention any two methods to avoid such diseases.
Q94. In human beings, the statistical
probability of getting either a male or a female child is 50 : 50.” Justify
this statement with the help of a diagram.
Q95. Explain the homologous and analogous
organs. Identify analogous and homologous organs amongst the following – wings
of an insect, wings of a bat, forelimbs of lizard, forelimbs of bird.
Q96. Define evolution. Why are traits acquired
during life time of an individual not inherited ?
Q97. The refractive indices of
alcohol and turpentine oil with respect to air are 1.36 and 1.47 respectively.
Find the refractive index of turpentine oil with respect to alcohol. In which
of the two medii the speed of light will be more ?
Q98. (a) Define power of a lens and
give its units. (b) A convex lens forms a real and inverted image of a needle
at a distance of 50cm from it. Where is the needle placed in front of this lens
if the image is equal to the size of the object ? Also find power of the lens.
Q99. The given figure shows an experimental
set-up for observing a phenomenon of light in colloidal solutions S : Strong
source of white light, L1 : Convex lens to provide a parallel beam of light, L2
: Convex lens to converge light on the screen MN, C : Circular hole in a
cardboard, T : Transparent glass tank. A student dissolves about 200 g of
sodium thiosulphate (hypo) in about 2L of clean water in the tank and adds
about 1 to 2 mL conc. H2SO4 to the water. What would he observe after the
source of light S is switched on – (i) from the three sides of the glass tank ?
(ii) from the fourth side of the glass tank facing the circular hole ?
Q100. (a) Draw electron dot structure
for oxygen molecule. (b) Mention the cause of hardness of water. (c) Mention
the name and the formula of second member of homologous series of alkanes. Q101.
Two elements X and Y belong to groups 1 and 3 respectively in the same period,
compare these with respect to their : (a) metallic character (b) size of the
atoms (c) formulae of their oxides and chlorides.
Q102. What is Placenta in human female ?
Explain its structure and functions.
Q103. Explain in brief the factors
that can lead to the rise of new species.
Q104. (a) Write a test to distinguish
between Ethanol and Ethanoic acid. (b) Draw electron dot structure of ethane.
(c) Why do soaps form scum with hard water ?
Q105 Explain with the help of diagram how sex
of a child is determined at the time of conception in human beings.
Q106. What are homologous organs? How do they
provide evidence in support of evolution?
Q107 From the part of a periodic
table, answer the following questions : (a) Which is the most reactive metal ?
(b) Name the family of fluorine Q,R,T. (c) Name one element each of group 2 and
15. (d) Give the name of the element P placed below Carbon. (e) Compare X and P
with respect to size of atoms. Q108 (a) Name any two plants that reproduce by
Grafting. (b) List any two benefits to an organism that reproduces through
spores ?
Q109. A tall red seeded Plant (TTRR) is
crossed to a short white seeded plant (ttrr). Find out phenotypes and genotypes
of F1 and F2 generation with a cross.
Q110. Write three differences between
acquired and inherited traits.
Q111. (a) Define speciation. (b) What is micro
evolution ? Does it explain speciation ?
Q112. (a) Name and define the S.I.
unit of power of a lens. (b) How is the power of a lens related to its focal
length ? Find the power of a concave lens of focal length 25 cm.
Q113. (a) State Snell‟s law of
refraction. (b) What is the speed of light in a transparent medium which has a
refractive 10 m/s)3index of 1.7 (the speed of light in vacuum is 3
Q114. (a) Draw a ray diagram to
represent how a narrow beam of white light after dispersion through a prism can
be made to recombine as white light. (b) Name the defects of vision when a
person can not see clearly : (i) the nearly objects (ii) the distant objects
(c) A person suffering from a defect of vision uses a corrective lens of power
– 2D. Find the nature and focal length of the corrective lens.
Q115. (a) An object 1 cm high
produces a real image 1.5 cm high when placed at a distance of 15 cm from a
concave mirror. Calculate the position of the image and the magnification. (b)
Write two uses of concave mirrors.
Q116. (a) A ray of light travelling
from a medium X enters obliquely into another medium Y. If it bends away from
the normal then state which one of the two is relatively optically denser. Why
? (b) Light enter from air to diamond 108 m/s.3having refractive index 2.42. Find the speed of light in diamond. The
speed of light in air is 3
Q117. What is hypermetropia ? Draw ray
diagrams to show the image formation of an object by : (i) Hypermetropic eye,
(ii) Correction made with a suitable lens for hypermetropic eye.
Q118. (a) What are hydrocarbons ? Give
one example. (b) Mention the structural difference between saturated and
unsaturated hydrocarbons. Write two examples of each.
Q119. (i) An atom has electronic
configuration 2 , 8 , 7. What is the atomic number of this element ? To which
of the following elements would it be chemically similar ? [N(7), F(9), P(15),
Ar(18)] (ii) How would the tendency to gain electrons change as you go from
left to right across a period ?
Q120 Draw a neat diagram showing
longitudinal section of a flower and label anther, Ovary, petal, stigma, sepal
and filament.
Q121. Explain various factors which
could lead to the formation of new species
Q122 (a) What are Fossils ? (b)
Explain various ways of estimating the age of fossils.
Q123. (a) Name any four varieties of
vegetables which have been produced from „wild cabbage‟ by the process of
artificial selection. (b) Give one example of an evolutionary change produced
in an organism for one purpose which later on become more useful for different
functions.
Q124. (i) Define magnification
produced by a lens. What does the negative sign of magnification signify ? (ii)
An object placed 30 cm from a lens forms an image on a screen placed 60 cm on
the other side of the lens. Identify the type of the lens and find its focal
length.
Q125. A coin is kept at the bottom of
an empty bucket. A student standing near to it cannot see the coin. Another
student pours some water into the bucket without disturbing the coin. Now the
first student is able to see the coin from the same position. Explain how it
became possible to see the coin now ? Draw a ray diagram to illustrate it.
Q126. (i) State two main causes due
to which a person may develop nearsightedness or myopia. With the help of a ray
diagram, suggest how this defect can be corrected ? (ii) The far point of a
myopic person is 100 cm. Calculate the power of a lens required to enable him
to see distant objects clearly. Q127 An organic compound X is an essential
constituent of wine and beer. X is responsible for intoxication caused by these
drinks. Oxidation of X yields an organic acid Y which is present in vinegar.
Name the compounds X and Y and write their structural formulae.
Q128 State Modern Periodic Law.
Mention the total number of groups and periods respectively in Modern Periodic
Table. Mention the names of elements of first period.
Q129 Draw a neat diagram of
human-female reproductive system and label on it Uterus, Cervix, Oviduct and
ovary.
Q130 (a) Define Fossil. (b) What are
homologous organ ? How do these organs provide evidences in favour of evolution
?
Q131. (a) Mention the name of food
plant from which cauliflower and Kohlrabi were evolved. (b) Mention the traits
on the basis of which these crops are selected artificially ?
Q132 A round green seeded plant
(RRyy) is crossed to a wrinkled yellow (rrYY) seeded plant. Findout phenotypes
and genotypes in F1 and F2 generation with the help of a cross.
Q133 (i) Why do we prefer to use :
(a) a convex mirror as a rear view mirror in vehicles ? (b) a concave mirror in
search lights ? (ii) Give the value of (a) the angle of incidence, and (b) the
angle of reflection for normal incidence of light on a concave mirror
Q134 (i) State Snell’s law of
refraction. (ii) In the given figure, identify the medium that is optically
denser. Give reason for your answer
Q135 A student sitting at the back of
the classroom cannot read clearly the letters written on the blackboard. What
kind of defect in vision is she suffering from ? State two causes of this
defect. Draw ray diagram for the correction of this defect.
Q136What is rancidity ? Mention any
two ways by which rancidity can be prevented ?
Q167Differentiate between strong and
weak acids. Identify the strong and weak acids from the following list of
acids. Hydrochloric acid, acetic acid, formic acid, nitric acid
Q138(a) Explain the formation of
ionic compound CaO with electron dot structure. Atomic number of calcium and
oxygen are 20 and 8 respectively. (b) Name the constituent metals of bronze. so
that the combination has a resistance of (i) 9 V
Q139. How you would connect three
resistors each of resistance 6 ? Justify
your answer. V(ii) 4 V Q140(a) Define
electric power. A device of resistance R is connected across a source of V
voltage and draws a current I. Derive an expression for power in terms of
voltage and resistance. (b) An electric bulb is connected to a 200 V generator.
The current is 0.5 A. What is the power of the bulb ?
Q141Define a solenoid. With the help
of a suitable diagram show the pattern of magnetic field lines around a current
carrying solenoid. State the region where field is uniform.
Q142List the events that occur during
the process of photosynthesis.
Q143(a) State the function of plant
hormones. Name a plant hormone which is essential for cell division ? (b) Name
the hormone which is involved in phototropism. Explain its role.
Q144(a) Identify the glands that
secrete (i) insulin (ii) thyroxin (b) Explain with an example how the timing
and amount of hormone secreted are regulated in human body.
Q145Explain three disadvantages of
burning fossil fuels.
Q146 List three characteristics of a
good source of energy and mention any three qualities of a good fuel.
Q147 A small amount of quick lime is
added to water in a beaker. (a) Name and define the type of reaction that has
taken place. (b) Write balanced chemical equation for the above reaction. Write
the chemical name of product obtained. (c) State two observations that you will
make in the reaction.
Q148 Write balanced chemical equation
for the reactions that take place during respiration. Identify the type of
combination reaction that takes place during this process and justify the name.
Give one more example of this type of reaction.
Q149 A compound which is prepared
from gypsum, has the property of hardening when mixed with right quantity of
water. (i) Identify the compound and write its chemical formula. (ii) Write the
chemical equation for its preparation. (iii) List any two uses of the above
compound.
Q150 Give reasons for the following :
(i) Ionic compounds have high melting point and boiling point. (ii) Ionic
compounds conduct electricity in molten state. (iii) Ionic compounds are solids
at room temperature and are somewhat hard.
Q151 A resistance wire is stretched
to double its length so that its area of cross – section is halved. How will
its resistance change ? Will any change be observed in its resistivity? Justify
your answer.
Q152 For the circuit diagram given below :
Calculate : (i) Value of current flowing through each resistor, (ii) The total
current in the circuit, (iii) The total effective resistance of the circuit.
Q153 Explain the function of fuse in
a domestic electric circuit ? An electric oven having power rating 2000 W, 220V
is used in an electric circuit, having a fuse of 5A rating. What is likely to
happen when the oven is switched on ? Explain.
Q154 In human alimentary canal name
the site of complete digestion of various components of food. Explain the
process of digestion.
Q155 Name the property that causes tendril to
circle around the object ? Explain how it happens and how is plant benefitted
by it ?
Q156 Smita’s father has been advised
by a doctor to reduce his sugar intake. (i) Name the disease he is suffering
from and name the hormone whose deficiency causes it. (ii) Identify the gland
that secretes it and mention the function of this hormone. (iii) Explain how
the time and amount of secretion of this hormone is regulated in human system
Q157 Distinguish between renewable
and non-renewable sources of energy. Also give an example of each of these
sources.
Q158. (i) Why are solar heating
devices painted black ? (ii) Name two such devices and state two limitations of
these.
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