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Which
device is always connected in series with the resistance?
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In
the following circuit, what the parts X and Y denote?
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What
is the colour of aluminium in pure state?
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During
the preparation of hydrogen chloride gas on a humid day, the gas is usually
passed through the guard tube containing calcium chloride. What is the role of
calcium chloride taken in the guard tube?
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Which
part shows stomatal pore in the following?
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What
does the pH of soft drink indicates?
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What
happens to the temperature of the solution when a solution of an acid is mixed
with a solution of a base in a test tube?
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Why
is it advised that never allow the current to flow for a long time in the
resistance wire?
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Why
does a compass needle get deflected when brought near a bar magnet?
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Define
metalloid.
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Name
the hormone which is secreted by thyroid gland.
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Give
two drawbacks of hydel power.
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(a)
Soft iron is not used for making a permanent magnet. Why?
(b)
Point out the direction of magnetic field lines inside the magnet.
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Two
students perform the experiments on series and parallel combinations of two
given resistors
and
and the
following
graphs
are obtained.
Which
of the graph is/are correctly labelled in terms of the words series and
parallel? Justify your answer.
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(a)
When a white powder was mixed with dilute acid, a colourless and odourless gas
was produced which turned lime water milky. What is this white powder?
(b)
Which one of the following set ups is the most appropriate for the evolution of
hydrogen gas and its identification?
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A
teacher gave two test tubes, one containing water and the other containing sodium
hydroxide solution, to the students and asked them to identify the test tube containing
sodium hydroxide solution.
Which
substance can be used to identify the test tube? Give the test.
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(a)
A student took four test tubes containing solutions of different colours marked
I, II, III and IV as shown below. Which test tubes could be containing copper sulphate
solution and ferrous sulphate solution?
(b)
A student performed the following four experiments.
In
which experiments, would he find the formation of a solid deposition?
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This
activity proves and shows that living plants absorb water from the soil and
water gets transported to the leaves and loss of water takes place by leaves i.e.,
transpiration.
Based
on the above activity, give the answers of the following questions.
(a)
Why transpiration is necessary for the plants?
(b)
What is transpiration pull?
-
Describe
an activity to demonstrate that iron is more reactive than copper.
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Balance
the given equations.
(a)
(b)
(c)
-
What
are organic acids? Give two examples. Why should acids not be stored in metal
containers?
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How
is sodium hydroxide prepared? Give its uses.
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Determine
the equivalent resistance between A and B.
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An
electric iron is marked 100 W, 200 V It is used for 30 min daily. Calculate its
resistance and energy consumed in kWh per day.
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Explain
the role of
(a)
saliva
(b)
trypsin
(c)
gastric juices in digestion
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Name
a safety device commonly used in electric circuits. Explain its working.
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Give
three examples of responses of plants to external stimulus.
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State
the composition of biogas. Give four uses of biogas.
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What
is the role of respiratory pigment in respiration? Give one example.
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Hormones
are needed by our body in an appropriate amount. Slightly more or less
secretion causes disorder in our body. Illustrate this by using three examples.
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During
the reaction of some metals with dilute hydrochloric acid, following observations
were made
(a)
Silver metal does not show any change.
(b)
The temperature of the reaction mixture rises when aluminium (Al) is added.
(c)
The reaction of sodium metals is found to be highly explosive.
(d)
Some bubbles of a gas are seen when lead (Pb) is reacted with the acid.
(e)
A gas is produced when sodium carbonate is added to the acid.
Explain
these observations giving suitable reasons.
Or
Write
chemical equations representing each of
(a)
combination reaction.
(b)
thermal decomposition reaction.
(c)
double displacement reaction.
(d)
neutralization reaction.
e)
redox reaction.
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Yashoda
makes potato chips for Kishan and stores them in a pot. She sees after sometime,
that the chips got spoiled. She was disappointed and then Kishan told her, how
this happened?
(a)
State values of Yashoda.
(b)
Which values of Kishan must be praised?
(c)
How do you store food at home?
Or
Mitali got
silver anklets made for her and kept them in cupboard. After a few days, when
she took them out for wearing, their colour was changed. She went to her mother
to tell her that they were fooled by jeweller. Her mother asked her reason to
feel so and told her, why this happened?
(a) Throw light on values of Mitali.
(b) Which
values of her mother must be praised?
(c)
Why did the colour of anklets change?
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Hamida
says her father that food synthesized in leaf by plant is transported to
various parts. To help him explain the mechanism of translocation in plants.
Or
Define
the terms nutrition and nutrients. List one difference between holozoic
nutrition and saprophytic nutrition. Give two examples of each of these two
types.
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What
is the relation between resistanced and current potential difference? Give
SI unit of resistance.
Draw
graph for
following data. Give two examples of conductors which obey Ohm's law.
|
I
|
0.2
|
0.4
|
0.6
|
0.8
|
1.0
|
1.2
|
1.4
|
|
V
|
0.8
|
1.6
|
2.4
|
3.2
|
4.0
|
4.8
|
5.6
|
Or
What
is electromagnet?
How
is it used in a scrap yard? How is strength of electromagnet increased?
On
what principle is electromagnet based?
-
Define
electric circuit. Draw symbols for
(a)
bulb
(b)
battery
(c)
close plug key
(d)
ammeter and connect them to form a circuit.
Or
(a)
The flow of current in a circular wire creates a magnetic field at its centre.
How
can existence of this field be detected? State the rule which helps to predict
the direction of magnetic field.
(b)
Represent uniform magnetic field and non-uniform magnetic field using a diagram.
What does the density of field lines in a region indicate?
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(a)
Name the places of our country where fields of natural gas are found. Why is it
called a clean fuel? Give two reasons.
(b)
Why is there so much emphasis on changing over from petrol/diesel driven
automobiles to CNG driven vehicles.
Or
(a)
(i) What conversion of energy takes place in wind mill?
(ii)
What is the minimum wind velocity required to obtain useful energy with a
windmill?
(iii)
Give one limitation of windmill.
(b) Hydro
energy is an indirect source of solar energy. Justify.
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