Time : 3 hours Max
Marks: 80
SECTION 'A'
1. (A) Answer the following sub - questions. (5 Marks)
1. The device used for
producing current is called a ..................... .
(a)
voltmeter (b) ammeter (c) galvanometer (d) generator
2. At the time of short
circuit, the current in the circuit ..................... .
(a) increases
(b) decreases (c) remains (d) increases in steps
3. The direction of the
magnetic field around a straight conductor carrying current is given by
.....................
(a) right hand rule
(b) Fleming’s left hand rule (c) Fleming’s right hand rule (d) none of these
4. The relation between
electricity and magnetism was first established by ..................... .
(a)
Ohm (b) Ampere (c) Oersted (d) Moseley
5. The region around magnet is
called as .............. .
(a)
magnetic Area (b) magnetic field (c) magnetic
loop (d) magnetism
(B) Rewrite the following statements by selecting the correct options: (5 Marks)
1. The image formed by a
concave mirror is ..................... .
(a)
always virtual and erect
(b)
always virtual and inverted
(c) virtual if the object is placed between pole and focus
(d)
virtual if the object is beyond focus
2. A concave mirror forms a
virtual image of an object placed ..................... .
(a) at
infinity
(b) at
the centre of curvature of the mirror
(c) at
the focus of the mirror
(d) between the focus and the mirror
3. A convex mirror always forms
an image which is ..................... than the object size.
(a) larger
(b) smaller
(c)
double
(d)
three times
4. No matter how far you stand
from a spherical mirror, your image appears erect. The mirror may be ...........
(a) Plane
(b)
concave
(c) convex
(d)
either plane or convex
5. In case of a concave mirror, an erect image
is ..................... .
(a) real and enlarged
(b)
real and diminished
(c)
virtual and diminished
(d) virtual and enlarged
2. Attempt the following. (10 Marks)
1. Atomic size increases down
the group.
i. The
atomic numbers of the elements increase as we go down the group. Thus, the elements
placed lower have more electrons.
ii. To
accommodate these electrons new shells are added to the atom.
iii.
These new shells take the outermost electrons farther from the nucleus causing
atomic size (radius) to increase as we go down the group.
2. What is the importance of a
chemical equation?
Ans. A
chemical equation can convey the following information.
i.
Reactants and products involved in the reaction.
ii.
Symbols and formulae of all substances involved in the reaction.
iii.
Relative number of reactants and product participating in the reaction.
iv.
Relative masses of reactants and products.
v.
Physical states of reactants and products.
3. Write short notes on
Indicators (with proper example).
Ans.
The acidic and basic nature of the compounds can also be indicated by some
natural as well as chemical substances. They are known as indicators.
i.
There are many natural substances such as rose petals, turmeric, beet root, etc
that can be used as indicators. They are called natural indicators.
ii.
Some chemical substances such as phenolphthalein, methyl orange, eosin are
synthetic
indicators.
iii.
Olfactory indicators: Substances whose odour changes in acidic or basic
solution are
called
olfactory indicator. An olfactory indicator works on the principle that when an
acid or base
is added to it, then its odour cannot be detected. Examples: onion and clove
extract.
iv.
Universal indicators: Universal indicator is a mixture of several indicators
which gives different colours at different pH values of the pH scale.
v.
Uses of indicators: The acidic or basic nature of a compound can be judged. It
is used in agriculture to determine the pH of the soil.
4. Give Scientific Reason : The
material used for fuse has low melting point.
i. A
fuse is used to protect a circuit and the appliances connected in the circuit
by stopping the flow of an excess electric current. For this, a fuse is
connected in series in the circuit.
ii.
When the current in the circuit passes through the fuse, its temperature
increases. When the current exceeds the specified value, the fuse must melt to
break the circuit. For this, the material used for a fuse has low melting
point.
5. Define
1.
Magnetic field: - The region around magnet, in which the force of attraction
and repulsion exists, is called as ‘magnetic field’.
2.
Solenoid: - A coil of many turns of insulated copper wire wrapped in the shape
of cylinder is called a solenoid.
3. Attempt the following. (10 Marks)
1. Refraction observed in the
atmosphere.
i. In
the atmosphere, there are different layers of air with different refractive
indices which keep on changing as the physical conditions of air are not
stationary (still).
ii.
When we observe any object through this air, the light coming from them refract
randomly due to which the apparent position of the object fluctuates.
iii.
The large scale effect of this phenomenon is the twinkling of stars, advanced
sunrise and delayed sunset.
iv.
Due to change in the refractive index of atmosphere, the intensity of light
that reaches our eyes from the stars varies and hence the stars appear
twinkling at night.
v.
Advanced sunrise occurs as a ray of light from the sun enters the earth’s
atmosphere; it follows a curved path due to refraction before reaching to the
observer.
vi. It
appears to the observer as if the rays are coming from the position where the
sun is seen by the observer, hence, the sun is seen earlier before it reaches
the horizon.
2. Explain Hypermetropia with
its correction.
i. It is
the defect in which human
eye can see distant objects clearly but is unable to see nearby objects
clearly.
ii. The
image of near object falls behind retina. Two possible reasons of Hypermetropia
are :
Weak
action of Ciliary muscles causes low converging power of eye lens.
The
distance between eye lens and retina decreases on account of either shortening
of eyeball or
flattening of lens. In this case focal length of the eye lens is too long.
A convex
lens of suitable focal length can correct this defect.
The rays coming from nearby object
are first converged by convex lens and then converged by eye lens to retina.
3. State any 5 Application of
Convex lens.
·
Simple microscope: A single convex lens of small focal length can be used as a
simple microscope. A magnification of about 20 times is obtained by simple
microscope. Watch repairers, jewelers, etc use it.
·
Compound microscope: A combinations of two convex lenses having short focal
lengths are used in compound microscope. It is used to observe bacteria,
viruses, cells, micro – organisms, etc.
·
Telescopes: A combination of two convex lenses is used in telescopes. An
astronomical telescope is used to get detailed view of astronomical bodies like
planets, stars, etc. Terrestrial telescope is used to study terrestrial
objects.
·
Optical instruments: Convex lenses are used in different optical instruments
like camera, projector, spectrometer, etc.
·
Spectacles: Convex lens is used in spectacles to correct defect like Hypermetropia
4. Explain the sign conventions
for reflection by spherical mirrors.
According to the new Cartesian sign
convention, the pole (P) of the mirror is taken as origin. The principal axis
is taken as X-axis of the co-ordinate system. The sign conventions are as
follows:
· The
object is always placed on the left of the mirror.
· All
distances parallel to principal axis are measured from the pole of the mirror.
· All
the distances measured to the right of the origin are taken as positive, while
distances measured to the left of the origin are taken as negative.
·
Distances measured perpendicular to and above the principal axis are taken as
positive.
·
Distances measured perpendicular to and below the principal axis are taken as
negative.
·
Focal length of convex mirror is positive while that of concave mirror is
negative.
5. Distinguish between Myopia
and Hypermetropia
Myopia
|
Hypermetropia
|
1. In this defect human eye
can see nearby objects distinctly but is unable to see distant objects clearly.
2. Image of distant object is
formed in front of retina.
3. Eye ball is
lengthened or lens is curved.
4. This defect is corrected
using concave lens.
|
1. In this
defect human eye can see distant objects
distinctly but
is unable to see nearby objects
clearly.
2. Image of
nearby objects falls behind retina.
3. Eye ball is
shortened or lens is flattened.
4. This defect
is corrected using convex lens.
|
Q4. Attempt the following (any 1) ( 5 marks)
1. How could the modern
periodic table remove various anomalies of Mendeleev’s periodic table?
i.
Hydrogen was placed in group 1 and in group 17 as it resembles alkali metals as
well as halogens. Therefore, no fixed position could be given to hydrogen in
Mendeleev’s periodic table. But in
Modern periodic table it is placed in group 1.
ii.
Mendeleev arranged the elements in their increasing order of atomic masses. But
some elements with higher atomic masses are placed before those having lower
atomic masses. E.g. Cobalt (Co) with atomic mass 58.93 is placed before Nickel
(Ni) having atomic mass 58.71. But in Modern periodic table the elements were
arranged on the basis of the atomic number of elements. Thus atomic number of
Co is 27 and that of Ni is 28. So Nickel is placed after Cobalt.
iii.
Though isotopes of the same elements have different atomic masses, they cannot
be placed separately in the periodic tale. Since isotopes are chemically
similar, they had to be given the same position in the periodic table. Isotopes
occupy the same position in the Modern periodic table.
iv. In
Modern periodic table elements are classified according to their electronic
configuration into different blocks. Thus, various anomalies (irregularity)
which were seen in Mendeleev’s table due to the arrangement according to atomic
masses were overcome by the Modern Periodic table.
2. Take finely powdered
Zinc and allow it to react with CuSO4 solution. Then take Zinc
granules and carry out the same reaction. Which reaction will take place faster
and why?
Ans.
i.
The reaction between powdered zinc
and copper sulphate solution is faster than that between zinc granules and
copper sulphate solution.
ii.
This is because one of the factors
that control the rate of reaction is the size of the particles. The smaller the
particles, the faster s the reaction.
iii.
Zinc granules are larger than
powdered zinc. Hence, the rate of reaction is faster when powdered zinc is
used.
Section B
5. (A) Say true or false with reason (5 Marks)
*1. In .....................
mode of reproduction, the offsprings are with minor differences. (Asexual)
*2. Both the parents contribute
equal amount of ..................... material to the offspring. (
*3. Dominant character masks
the ..................... character. (Recessive)
*4. Selection by nature is not
..................... but ..................... . (Deliberate, natural)
5. Mendel’s experiments were
based on a number of visible contrasting characters of garden peas _________ (Pisum sativum)
(B) Say true or false with reason (5
Marks)
1. A fragment of DNA that
provides complete information about one protein is known as the .....................
for that protein. (
2. All children inherit
..................... chromosome from their mother. (
3. 3. Sex determination in
human beings is ..................... . (
4. ..................... are
collected from different levels of depths. (Fossils)
5. Minor differences occur in
asexual reproduction due to inaccuracies occuring in ..................... . (DNA copying)
6. Attempt the following. (10 Marks)
1. State two functions of MPCB
for prevention of water pollution.
MPCB
is the Maharashtra Pollution Control Board. Their functions are:
i. To
plan comprehensive programmes for the prevention, control or abatement of
pollution.
ii. To
inspect sewage or trade effluent treatment and disposal facilities.
iii.
To support and encourage the developments in the fields of pollution control,
waste recycle, reuses, eco – friendly practices, etc.
iv. To
educate and guide the entrepreneurs in improving environment by suggesting appropriate
pollution control technologies and techniques.
v. To
create public awareness about the clean and healthy environment and consider
the public complaints regarding pollution.
2. Define eco – efficiency.
What are the ways to achieve eco – efficiency?
Eco –
efficiency mean the creation of goods and services using fewer resources and
creating less waste. Eco – efficiency can be achieved by:
i. Use
of alternative raw materials: e.g. Agricultural residues like rice straw and
wheat straw are good substitutes for wood.
ii.
Shifting to renewable sources of energy: e.g. renewable sources of energy such
as biofuels, solar power, wind power, tidal power, hydropower, geo – thermal
power etc. do not create pollution and are inexhaustible.
iii.
Technology that reduces pollution: e.g. solar water heater, solar cooker, wind
mills etc. Are examples of pollution free technologies. Use of CNG and unleaded
petrol in vehicles also reduces pollution.
iv.
Reusing and recycling waste: e.g. waste products like paper, glass, plastics
and metals can be recycled to make new products.
v.
Durable goods: e.g. use of fibre optic cables in place of copper telephone wire
not only reduces the use of mineral sources but also provides better
communication.
3. Give the impacts of Noise pollution on the
human body.
Effects
of noise pollution on human beings depend on noise intensity, frequency and
exposure duration.
There
are three types of effects on man:
i. Auditory effects: Auditory fatigue, deafness.
ii. Non – auditory effects: Communication interference,
sleep interference, concentration interference, ill temper, annoyance, violent
behaviour, mental disorientation, bickering and lose of working efficiency.
iii.
Physiological effects: Nausea, fatigue, anxiety, visual disturbances, insomnia, hypertension,
cardio vascular disease.
4. Distinguish between
Degradable and Non degradable pollutants.
Degradable
pollutants
|
Non
degradable pollutants
|
1.
Degradable pollutants can be decomposed or degraded
easily.
2.
Decomposition takes place by microorganisms and it
requires less time.
3.
These pollutants again enter the biogeochemical cycles
and become part of the natural nutrient cycle.
|
1.
Non – degradable pollutants cannot be easily
decomposed.
2.
It requires more time and different techniques for
decomposition.
3.
These pollutants will remain on the earth for years
and create environmental pollution.
|
5. What are the advantages of
sexual reproduction over asexual reproduction?
i. The
offsprings produced by sexual reproduction are different from parents.
ii.
Variations give rise to variety and diversity.
iii.
Variation enables organisms to adapt and survive in the changing environment.
iv. It
helps to prevent the complete extinction of animal and plant species.
7. Attempt the following. (10 Marks)
1. Write the functions of
a. Vagina
i. It
provides the route for the menstrual blood to leave the body during
menstruation.
ii. It
is a pathway through which sperms enters into woman’s body.
iii.
It is a pathway through which a baby comes out of the woman’s body during child
birth.
b. Stigma
i. It
receives pollen grains and on which pollen germinates.
c.
Ovaries
i. Ovaries
develop and release eggs into the oviduct.
ii. It
secretes hormone estrogen.
2. Write short notes on Reflex
action
· The
sudden action in response to some happenings in the environment is called as
reflex action.
· It
is an involuntary action which we perform automatically.
· The
path way taken by nerve impulses in a reflex action is called reflex arcs.
Reflex arcs allow rapid response.
· A
nerve from all over the body meet in a bundle in such a connection is commonly
called as the spinal cord, before impulses are sent to the brain.
·
Hence, reflex arcs are formed in the spinal cord, although the messages reach
the brain.
·
Pulling away our hand on touching a hot object, narrowing of the eyes in
sunlight, watering of the mouth on smelling something delicious etc. are
examples of reflex action.
3. Explain the structure and
function of a nephron.
· The
basic filtration unit in the kidney is a cluster of thin walled blood
capillaries called as nephron.
· Each
nephron has a cup shaped thin walled upper end called Bowman’s capsule which contains
a bundle of blood capillaries called glomerulus.
· When
blood containing urea enters the glomerulus it gets filtered through glomerular
capillaries.
· The
selectively permeable wall of the Bowman’s capsule allows the water molecules
and small molecules of the other substances to pass through them and forms
glomerular filtrate.
· The
blood, free from these materials is taken to the heart through the renal vein.
· The
glomerular filtrate collected in the Bowman’s capsule further passes through
the nephron tubule where reabsorption of water and useful molecules take place.
· The
remaining fluid containing the waste forms the urine which eventually enters a
long tube called the ureter.
· It
is further stored in the urinary bladder and from there it is thrown out
through the
urethra.
4 . Differentiate between:
Detergents and soaps
Detergents
|
Soaps
|
i.
Detergents are generally
ammonium or sulphonate salts of long chain carboxylic acids.
ii.
Detergents have a strong
cleansing action.
iii.
Oils or fats are not used
in their manufacture; usually petrochemicals are used to produce detergents.
iv.
They function well in
hard or soft water.
|
i.
Soaps are sodium or
potassium salts of long chain carboxylic acids.
ii.
Soaps have relatively
weak cleansing action.
iii.
Vegetable oils or animal
fats are used along with hydroxide of sodium or potassium to manufacture
soaps.
iv.
They do not work well in
had water but work well in soft water.
|
5. Give scientific reasons :
Calcium floats over water during the reaction with water.
Ans.
i.
Calcium reacts with water less vigorously so that the heat evolved is not
sufficient for the hydrogen formed, to catch fire.
ii.
Instead, calcium starts floating because the bubbles of hydrogen gas formed
stick to the surface of the water calcium.
8. Attempt the following (5 marks.)
1. Explain about Darwin’s
theory of evolution. Or Darwin's theory of Natural Selection.
·
Darwin's theory of evolution is better known as theory of Natural selection.
·
Darwin opined that only the fittest can survive. Those plant and animals which
are not fit for survival, die.
· The
fitter species reproduce in greater numbers and pass on their genes to the next
generations. This process of selection of characteristics which contribute to
the fitness for survival was termed as natural selection.
·
Darwin's theory of Natural selection emphasises on the fact that there is
always overproduction of individuals in nature. This causes struggle for
existence. Only those organisms that have characters useful for survival are
selected and hence they survive.
While
some organisms that do not have favourable characters, perish. This process
takes place for many generations.
· As a
result the species which are better adapted for survival are selected. The
individuals belonging to this species may be different from the original ones.
But if this changed species shows successful adaption and growth in the given
environment then it gets evolved.
· The
process of natural selection is not deliberate but is gradual and natural. This
process further leads to the development of species.
·
Darwin's theory is widely accepted but it has one drawback. It did not explain
how the favourable characters were developed in the fit individuals.
·
Darwin's theory is now universally accepted.
2. Given below are the end products of different reactions involving
glucose.
Write the
reaction number in front of the following:
1. Anaerobic reaction =
2. Reaction in human muscles =
3. Aerobic respiration =
4. Reaction in plant cells =
5. Reaction in liver =
Ans.
1. Anaerobic reaction = 5
2. Reaction in human muscles =4
3. Aerobic respiration = 3
4. Reaction in plant cells = 1
5. Reaction in liver = 2
