MODEL PAPER 1 Science - MODEL PAPER 1

Assertion (A): In an ecosystem, the function of producers is to convert organic compounds into inorganic
compounds.
Reason (R): Green plants, the producers, transduce solar energy.

Assertion (A): The magnetic field intensity at the centre of a circular coil carrying current changes, if the current through the coil is doubled.
Reason (R): The magnetic field intensity is dependent on current in conductor.

Assertion (A): Vaginal pills contain spermicides.
Reason (R): Spermicides kill the sperms.

Assertion (A): Stannous chloride is a powerful oxidising agent which oxidises mercuric chloride to mercury.
Reason (R): Stannous chloride gives a grey precipitate with mercuric chloride, but stannic chloride does not do so

In a given food chain, suppose the amount of energy available at the third trophic level is 50 KJ. What will be the energy available at the producer level?

Assertion (A): Stannous chloride is a powerful oxidising agent which oxidises mercuric chloride to mercury.
Reason (R): Stannous chloride gives a grey precipitate with mercuric chloride, but stannic chloride does not do so

Assertion (A): Vaginal pills contain spermicides.
Reason (R): Spermicides kill the sperms.

Assertion (A): The magnetic field intensity at the centre of a circular coil carrying current changes, if the current through the coil is doubled.
Reason (R): The magnetic field intensity is dependent on current in conductor.

Assertion (A): In an ecosystem, the function of producers is to convert organic compounds into inorganic
compounds.
Reason (R): Green plants, the producers, transduce solar energy.

What type of lens we wear if we are suffering from myopia ?

What is ozone and how does it affect any ecosystem?

Give some examples along with reasons of insecticides that are banned due to their fatal effects.

A concave lens has a focal length of 10 cm. An object 2.5 cm high is placed 30 cm from the lens. Determine the position and size of the image.

What are the two phases of photosynthesis reactions?

What is atmospheric refraction? Explain with the help of a labelled diagram that the position of a star as seen by us is not its true position.

In pea plant, round seed is dominant over the wrinkled. If a cross is carried out between these two plants, give answer to the following questions
i. Mention the genes for the traits of parents.
ii. State the trait of F₁ hybrids.
iii. Write the ratio of F2 progeny obtained from this cross. What is the name of the cross?

Draw the diagram of part of leaf from which transpiration takes place. Explain stomatal or foliar transpiration.

i. Compare soaps and detergents on the basis of their composition and cleansing action in hard water.
ii. What happens when ethanol is treated with sodium metal? State the behaviour of ethanol in this reaction.
iii. Draw the structure of cyclohexane.
iv. Name the following compound.

Differentiate between a concave mirror and a convex mirror.

What is lens formula? Give its sign conventions and assumptions.

Observe the above figure carefully and answer the following:
i. Which phenomenon does the figure represent?
ii. Which plant hormone is involved?
iii. How this plant hormone brings this movement?

Why are budding, fragmentation and regeneration all considered as asexual types of reproduction? With neat diagrams explain the process of regeneration in Planaria.

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.

Fill a conical flask with water. Cover the neck of the flask with a wire mesh. keep two or three freshly germinated bean seeds on the wire mesh. Take a cardboard box which is open from one side. Keep the flask a wire mesh. Kin the box in such a manner that the open side of the box faces light coming from a window as shown in the given figure. After two or three days, you will notice that the shoots bend towards light and roots away from light. Now turn the flask so that the shoots are away from light and the roots towards the light. Leave it undisturbed in this condition for a few days. 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.


(a) What has represented by the given activities?
(b) Do old parts of the shoot and root change direction? Is there any difference in the direction of the new growth?
(c) What can we conclude from this activity?
OR
What is geotropism?

Read the text carefully and answer the questions:
The teacher while conducting practicals in the laboratory divided the students into three groups and gave them various solutions to find out their pH and classify them into acidic, basic and neutral solutions.
Group A - Lemon juice, vinegar, colourless aerated drink
Group B - Tomato juice, coffee, ginger juice
Group C - Sodium hydroxide, sodium chloride, lime water
(a) For the solutions provided, which group is/are likely to have pH value (i) less than 7, and (ii) greater than 7?
(b) List two ways of determining pH of a solution.
OR
Explain, why the sour substances such as lemon juice are effective in cleaning the tarnished copper vessels.