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When n resistors of equal resistance R each
are connected in series, what will be the equivalent resistance?
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Why should the key be taken out
after taking the readings?
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What is the SI unit of potential
difference?
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What is nuclear fusion?
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Where does dark reaction of photosynthesis
occur?
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The leaf of a destarched plant is
covered with black paper strip. After 8 h, starch test is done. In which part
will the colour beblue-black?
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Name the process by which roots
absorb water from soil.
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Why is tungsten metal selected
for making filaments of incandescent lamp bulb?
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Which is the largest gland of
our body and what is its function?
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Compare the pH of oxalic acid
with seven.
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A blue litmus paper was first
dipped in dil. HC1 and then in dil. NaOH solution. What change in colour of
litmus paper you will observe?
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When zinc granules are kept in
copper sulphate solution, what change in colour of solution you will observe?
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(a) When do we put the
resistance in series combination?
(b) How will you find the
equivalent resistance of two resistors when they are connected in series?
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(a) What is the colour of
precipitate formed when, barium chloride reacts with sodium sulphate solution?
(b) Name this type of reaction.
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Which mechanism plays an
important role in transportation of water in plants?
(a) During daytime
(b) At night
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In the figure given below
(a) Which type of movement is
shown by the plant in above activity?
(b) The information below shows
the function of the responses of plants
To gain mineral salts in the
soil and to get support.
Name the response related with
the functions above.
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Name the green dot-like structures
in some cells observed by a student when a leaf-peel was viewed under a microscope.
What is this green colour due to?
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Write chemical formula for calcium
oxychloride. How is it prepared? What is its common name? What is its use?
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A non-metal A which is the largest
constituent of air, when heated with H2 in 1:3 ratio in the presence
of catalyst (Fe) gives a gas B. On heating with O2 it gives anoxide
C. If this oxide is passed into water in the presence of air, it gives an acid
D which acts as a strong oxidizing agent.
(a) Identify A, B, C and D.
(b) To which group of the
Periodic Table does this non-metal
belongs?
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Write chemical reaction for soda
acid fire extinguisher.
How does it work?
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How would you distinguish between
baking soda and washing soda by heating?
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An electric heater is rated at 2kW
Calculate the cost of using it for 2 hours daily for the month of September, if
each unit costs Rs. 4.00.
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Define electric power. An electric
motor takes 5 A from a 220 V line. Find the power of the motor and energy consumed
in 2 h.
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How does transpiration help in
the functioning of plant? A plant leaf was coated with Vaseline. What happens
to
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(a) On what factors, the
resistance of the conductor depends?
(b) What is (i) the highest,
(ii) the lowest resistors that can be secured by combinations of four coils of resistance
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What are the functions of
nervous system? Give two parts of vertebrate nervous system.
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A copper coil is connected to a galvanometer.
What would happen if a bar magnet is
(a) pushed into the coil with its North pole
entering first?
(b) held at rest inside the coil?
(c) pulled out again?
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How is biogas produced? Why is
it a better fuel than cow dung?
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(a) An iron nail is kept in
copper sulphate solution. What happens and why?
(b) A metal M does not liberate
hydrogen from acids but reacts with oxygen to give a black colour product.
Identify M and black coloured product and also explain the reaction of M with oxygen.
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Balance the following
chemical equations
(a)
(b)
(c)
(d)
(e)
Or
List six physical properties of
acids. How do acids react with metals?
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Malini stores curd in a
beautifully designed copper containers for a party in the evening. The guests complain
that curd has turned bitter. She gets embarrassed and feels sorry. One of the guests
told her why this happens, so that she would careful next time.
(a) What suggestion would have
been
(b) List values of Malini.
(c) What values are shown by the
guest?
Or
Manisha is experimenting with
acids in the lab. She is suggested by Nisha to wear lab coat and goggles which
she ignores. The acid spills over her dress and burns her hand too. Nisha immediately
rescues her by providing first aid and takes her to medical room.
(a) Throw light on values of
Nisha.
(b) What precautions should be
taken, while working in laboratory?
(c) Give examples of some strong
acids.
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Rohit's father told him that
various pipes are responsible for transport of blood in our body. But he thinks
that these are of single type. Describe the types of blood vessels present in
our body. Explain the function of each to help Rohit.
Or
Hemant says his grandmother that
water and minerals are transported from root to leaf in plant. To help his grandmother,
explain the mechanism of water and minerals transport in plant.
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(a) State the rule to determine
the direction of a
(i) magnetic field produced
around a straight conductor carrying-current.
(ii) force experienced by a
current-carrying straight conductor placed in a magnetic field.
(iii) current induced in a coil
due to its rotation in magnetic field.
(b) How will the 'magnetic force
get affected on
(i) doubling the magnitude
of current?
(ii) reversing the direction of
current flow?
Or
What are magnetic and
non-magnetic substances? Give two examples of each. What material is used to
make permanent magnet? How can electric current be used to magnetise a coil of
wire?
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An electric lamp has resistance
and
conductor of 40, resistance are connected in series to 6 V battery. Find
(a) total resistance of circuit.
(b) current through each
resistance.
(c) potential difference across
each resistor. Draw circuit diagram also.
Or
(a) State energy conversion
occurring in an electric motor.
(b) On what principle does a
motor work?
(c) Draw a diagram of electric
motor.
(d) Give two uses of electric
motor.
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Mention advantages and
disadvantages of producing hydro electricity by construction of dams.
Or
Explain the difference between nuclear
fusion and fission reactions with examples. Why can't energy due to fusion be
used to meet our day-to-day energy needs?
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