MODEL PAPER 10 Science - MODEL PAPER 10

Assertion (A): Recycling is the way of managing plastic waste.
Reason (R): Broken plastic articles are sent to plastic processing units where they are melted and remoulded to make new plastic articles.

Assertion (A): A compass is kept near a wire carrying current gets deflected
Reason (R): Electric current is capable of producing a magnetic effect.

Assertion (A): DNA copying is necessary during reproduction.
Reason (R): DNA copying leads to the transmission of characters from parents to offspring.

Assertion (A): Silver articles become black after sometime when exposed to sunlight
Reason (R): It is because silver reacts with carbonates present in the air.

Food web is constituted by

Assertion (A): Silver articles become black after sometime when exposed to sunlight
Reason (R): It is because silver reacts with carbonates present in the air.

Assertion (A): DNA copying is necessary during reproduction.
Reason (R): DNA copying leads to the transmission of characters from parents to offspring.

Assertion (A): A compass is kept near a wire carrying current gets deflected
Reason (R): Electric current is capable of producing a magnetic effect.

Assertion (A): Recycling is the way of managing plastic waste.
Reason (R): Broken plastic articles are sent to plastic processing units where they are melted and remoulded to make new plastic articles.

When a beam of white light is passed through a triangular glass prism, it gets dispersed into its seven colour
components. Why do we get these colours? In the given figure, the colours X and Y represent the extreme components of the spectrum. Identify X and Y.

In the given figure, the various trophic levels are shown in a pyramid. At which trophic level is maximum energy
available?

Your uncle has come from the village to renew the contract to supply frogs to the laboratories of the colleges of the town. While talking to you, he mentioned that cases of malaria have increased in his village. In addition population of grasshoppers has also increased who are damaging crops.
i. What could be the reasons for such problems faced by villagers?
ii. What suggestions will you give to your uncle?

Draw a ray diagram showing the path of rays of light when it enters with oblique incidence
i. from air into water,
ii. from water into air.

Differentiate between Respiration and Photosynthesis.

Derive the relation between kilowatt hour and joule.

Differentiate between virtual image formed by a concave mirror and of a convex mirror.

Explain how deoxygenated blood travels from body to lung for purification. Draw well-labelled diagram in support of your answer.

How phototropism does occur in plants?

Explain the term fission as used in relation to reproduction.

A student was asked to perform an experiment to study the force on a current carrying conductor in a magnetic
field. He took a small aluminum rod AB, a strong horse shoe magnet, some connecting wires, a battery and a
switch and connected them as shown. He observed that on passing current, the rod gets displaced. On reversing
the direction of current, the direction of displacement also gets reversed. On the basis of your understanding of
this phenomenon, answer the following questions :


(a) State the condition under which the displacement of the rod is largest for the same magnitude of current flowing through it.
(b) State the rule that determines the direction of the force on the conductor AB.
(c)
i. If the U shaped magnet is held vertically and the aluminum rod is suspended horizontally with its end
B towards due north, then on passing current through the rod from B to A as shown, in which direction will the rod be displaced?
ii. Name any two devices that use current carrying conductors and magnetic field.

OR

Draw the pattern of magnetic field lines produced around a current-carrying straight conductor held vertically on horizontal cardboard. Indicate the direction of the field lines as well as the direction of the current flowing through the conductor.

Environmental triggers such as light, or gravity will change the directions that plant parts grow in. These
directional, or tropic, movements can be either towards the stimulus or away from it. So, in two different kinds
of phototropic movement, shoots respond by bending towards light while roots respond by bending away from
it. How does this help the plant? Plants show tropism in response to other stimuli as well. The roots of a plant
always grow downwards while the shoots usually grow upwards and away from the earth. This upward and
downward growth of shoots and roots, respectively, in response to the pull of earth or gravity, is, obviously,
geotropism. If ‘hydro’ means water and ‘chemo’ refers to chemicals, what would ‘hydrotropism’ and ‘chemotropism’ mean? Can we think of examples of these kinds of directional growth movements? One
example of chemotropism is the growth of pollen tubes towards ovules, about which we will learn more when we examine the reproductive processes of living organisms.



(a) Where does negative phototropism occur in plants?
(b) Phototropism in shoots is attributed due to which plant hormone?
(c) Tendrils exhibit/ twining of tendrils show which type of tropic movement?

OR

If the stem grows towards sunlight and the root grows just opposite to it, then what type of movement of the stem is it?

Copper sulphate crystal contains water of crystallisation when the crystal is heated the water is removed and salt
turns white. The crystal can be moistened again with water. The water of crystallisation is the fixed number of
water molecules present in 1 formula unit of copper sulphate. On heating gypsum at 373K, it loses water
molecules and became calcium sulphate hemihydrate.



(a) If the crystal is moistened with water, then which colour of the crystal reappears?
(b) What is the commercial name of calcium sulphate hemihydrate?

OR

Five water molecules are present in one formula unit of copper sulphate.