P-2 Cell Biology and Biotechnology — Science STD 10 — Question

Observe the figure and answer the following questions


Question
(i) What are the masses of the objects shown?
(ii) What is the distance between their centres?
(iii) Write gravitational force between them.
(iv) Why gravitation constant is called universal constant?
(v) What will happen to gravitational force if mass of one of the objects is doubled?
(vi) What is the value of universal constant in SI?

Which projects will you run in relation to environmental conservatioh? How?
(OR)
Write six strategies implemented by you for conservation of the environment.

Whether the incidence shown in the following picture is rational? Express your opinion.

Write short note: Coelom.

Sketch, label and classify the following organisms: Liverfluke.

Read the given passage carefully and answer the questions.
We know that the force of gravity due to the earth acts on each and every object. When we were holding the stone in our hand, the stone was experiencing this force, but it was balanced by a force that we were applying on it in the opposite direction. As a result, the stone remained at rest. Once we release the stone from our hands, the only force that acts on it is the gravitational force of the earth and the stone falls down under its influence. Whenever an object moves under the influence of the force of gravity alone, it is said to be falling freely. Thus the released stone is in a free fall. In free fall, the initial velocity of the object is zero and goes on increasing due to the acceleration due to the gravity of the earth. During free fall, the frictional force due to air opposes the motion of the object and a buoyant force also acts on the object. Thus, true free fall is possible only in a vacuum.
1) Complete the following statement by choosing the right option.
The stone held in the hand is stable because on it __.

1. two unbalanced forces are exerted.
2. only the gravitational force of the earth is exerted.
3. gravitational force of the earth is not exerted.
4. two balanced forces are exerted.

2) Why does free fall not happen on the earth?
3) Why does the velocity of the object increase during the free fall?
4) Which type of force exerts on the object during free fall?
5) Why does free fall happen only in a vacuum?

There are two important fuels A and B both of which are extracted from deep inside the earth. Fuel A is a thick, dark, foul smelling liquid whereas fuel B is a black solid. Combustion of both the fuels produces products, C, D, E and F. The product C makes the rainwater only slightly acidic but it is mainly responsible for causing global warming. The product D is neither acidic nor basic. It is harmless and does not affect the environment in any way. Both E and F attack breathing system of humans and are mainly responsible for causing acid rain. In addition to combustion of fuels A and B, the product F is also formed when lightning occurs in the sky.

1. What are (i) fuel A, and (ii) fuel B?
2. Name (i) C (ii) D (iii) E, and (iv) F?
3. What is the process of formation of F during lightning known as?
4. Which fuel is supposed to be exhausted sooner : A or B?
5. Which fuel is mostly used for generating electricity at thermal power plants?

Complete the chart - Classification of living organisms

Calculate the amount of energy that will be available to big fish in the following food chain, if 10,000 J of energy is available to small algae from the sun:
Small algae —> Zooplankton —> Fish —> Big fish