A moving object can do work. An object moving faster can do more work than an identical object moving relatively slow. A moving bullet, blowing wind, a rotating wheel, a speeding stone can do work. How does a bullet pierce the target? How does the wind move the blades of a windmill? Objects in motion possess energy. We call this energy kinetic energy.Thus, the kinetic energy possessed by an object of mass, m and moving with a uniform velocity, v is KE=1 / 2 mv^2 The energy possessed by an object is thus measured in terms of its capacity of doing work. The unit of energy is, therefore, the same as that of work, that is, joule (J). (i) Energy possessed by body which is in motion is called (a) Potential energy (b) Kinetic energy (c) Nuclear energy (d) None of these (ii) Which of the following has same unit? (a) Potential energy and Force (b) Kinetic energy and work (c) Both a and b (d) None of these (iii) Kinetic energy depends (a) Inversely on velocity of body (b) Directly on square of velocity of body (c) Directly on velocity of body (d) None of these (iv) Define kinetic energy of body. Give its SI unit (v) Is kinetic energy scalar or vector? Justify your answer

(i) b (ii) b (iii) b (iv) Energy possessed by object due to its motion is called as kinetic energy. Its SI unit is N-m or Joule(J). (v) kinetic energy is scalar quantity as it is a work done and work done is scalar quantity hence kinetic energy is also scalar quantity and doesn’t have any direction.

A moving object can do work. An object moving faster can do more …

Read the following text carefully and answer the questions that follow:
The tissue is a group of cells having similar origin, structure\& function. Study of tissues is called Histology. In unicellular organism (Amoeba) single cell performs all basic functions, whereas in multi-cellular organisms (Plants and Animals) shows division of labour as Plant tissue \& Animal tissues. Plant tissues are two types:

Meristematic tissue: The meristems are the tissues having the power of cell division. It is found on that region of the plant which grows.
Following are the types of Meristems:
The Apical meristems- It is present at the growing tip of the stem and roots and increases the length.
The lateral meristems- It present at the lateral side of stem and root (cambium) and increases the girth.
The intercalary meristems- It present at internodes or base of the leaves and increases the length between the nodes.
i. Which tissue help in the secondary growth of the plant?
ii. In what region of the plant does intercalary meristematic growth occur?
iil. Where does meristematic tissue mostly found in a plant?

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The first level of classification among plants depends on whether the plant body has well differentiated, distinct parts. The next level of classification is based on whether the differentiated plant body has special tissues for the transport of water and other substances. Further classification looks at the ability to bear seeds and whether the seeds are enclosed within fruits.
THALLOPHYTA
Plants that do not have well-differentiated body design fall in this group. The plants in this group are commonly called algae. These plantsare predominantly aquatic. Examples are Spirogyra, Ulothrix, Cladophora, Ulva and Chara.
BRYOPHYTA
These are called the amphibians of the plant kingdom. The plant body is commonly differentiated to form stem and leaf-like structures. There is no specialised tissue for the conduction of water and other substances from one part of the plant body to another. Examples are moss (Funaria) and Marchantia.
PTERIDOPHYTA
In this group, the plant body is differentiated into roots, stem and leaves and has specialised tissue for the conduction of water and other substances from one part of the plant body to another. Some examples are Marsilea, ferns. The reproductive organs of plants in all these three groups are very inconspicuous, and they are therefore called ‘cryptogams’, or ‘those with hidden reproductive organs’. On the other hand, plants with welldifferentiated reproductive parts that ultimately make seeds are calledphanerogams. This group is further classified, based on whether the seeds are naked or enclosed in fruits, giving us two groups – gymnosperms and angiosperms.
Gymnosperms are the plants which bear naked seeds and are usually perennial, evergreen and woody. Examples are pines and deodar. Angiosperms are the plants which seeds are enclosed inside an ovary.
(1) Plants that do not have well-differentiated body is known as _________
$(a)$ Bryophytes
$(b)$ Pteridophytes
$(c)$ Thallophytes
$(d)$ Angiosperms
(2) The plants which bear naked seeds
$(a)$ Angiosperms
$(b)$ Gymnosperms
$(c)$ Thallophytes
$(d)$ Pteridophytes
(3) Phanerogams are further classified into
$(a)$ Angiosperms
$(b)$ Gymnosperms
$(c)$ Thallophytes
$(d)$ Both $a$ & $b$
(4) Which of the following is the distinguishing feature of Bryophytes
$(a)$ Plant body is differentiated to form stem and leaf-like structures
$(b)$ No specialised tissue for the conduction of water and food
$(c)$ Both $a$ & $b$
$(d)$ None of above
(5) Explain the three important aspect on which classification of Plantae?

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Carbon is found in various forms on the Earth. It occurs in the elemental form as diamonds and graphite. In the combined state, it is found as carbon dioxide in the atmosphere, as carbonate and hydrogen carbonate salts in various minerals, while all life-forms are based on carbon-containing molecules like proteins, carbohydrates, fatsnucleic acids and vitamins. The endoskeletons and exoskeletons of various animals are also formed from carbonate salts. Carbon is incorporated into life-forms through the basic process of photosynthesis which is performed in the presence of Sunlight by all life-forms that contain chlorophyll. This process converts carbon dioxide from the atmosphere or dissolved in water into glucose molecules. The utilisation of glucose to provide energy to living things involves the process of respiration in which oxygen may or may not be used to convert glucose back into carbon dioxide. This carbon dioxide then goes back into the atmosphere. Another process thatadds to the carbon dioxide in the atmosphere is the process of combustion where fuels are burnt to provide energy for various needs like heating, cooking, transportation and industrial processes. In fact, the percentage of carbon dioxide in the atmosphere is said to have doubled since the industrial revolution when human beings started burning fossil fuels on a very large scale. Carbon, like water, is thus cycled repeatedly through different forms by the various physical and biological activities.
$(1)$ Which process converts carbon dioxide from the atmosphere or dissolved in water into glucose molecules
$(a)$ Photolysis
$(b)$ Photosynthesis
$(c)$ Respiration
$(d)$ Nitrogen cycle
$(2)$Identify the correct statement
Statement $1 –$ Carbon is incorporated into life-forms through the basic process of Photosynthesis
Statement $2 –$ Photosynthesis is performed by all life-forms that contain Chlorophyll
Statement $3 -$Carbon occurs in the elemental form as diamonds and graphite.
Statement $4 $-Proteins and carbohydrates are carbon containing molecules.
$(a)$ Both $1 \& 4$
$(b)$ Both $2 \& 4$
$(c)$ Only $3$
$(d)$ All of the above
$(3)$ The endoskeletons and exoskeletons of various animals are made up of
$(a)$ Carbon Dioxide
$(b)$ Diamond
$(c)$ Graphite
$(d)$ Carbonate salts
$(4)$ What is the respiration?
$(5)$ Enlist the elemental form of carbon.

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There are three states of matter – solid, liquid and gas.
Solids have a definite shape, distinct boundaries and fixed volumes, that is, have negligible compressibility. Solids have a tendency to maintain their shape when subjected to outside force. Solids may break under force but it is difficult to change their shape, so they are rigid.
Liquids have no fixed shape but have a fixed volume. They take up the shape of the container in which they are kept. Liquids flow and change shape, so they are not rigid but can be called fluid.
Gas as has indefinite shape, no fixed volume. Gas gets the shape and volume of container.
Gas has very low density hence are light. Gas can flow easily and hence are called fluid.
$i.)$ Which of the following state of matter takes shape of container in which it is filled?
$a.)$ Solid
$b.)$ Liquid
$c.)$ Gas
$d.)$ Both $b$ and $c$
$ii.)$ Distance between particles of matter least in
$a.)$ Solid
$b.)$ Liquid
$c.)$ Gas
$d.)$ None of these
$iii.)$ Compressibility is least in case of
$a.)$ Solid
$b.)$ Liquid
$c.)$ Gas
$d.)$ None of these
$iv.)$ Give properties of solids.
$v.)$ Give properties of Gases.

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The form of energy can be changed from one form to another. What happens to the totalenergy of a system during or after the process?Whenever energy gets transformed, the totalenergy remains unchanged. This is the law ofconservation of energy. According to this law, energy can only be converted from one form to another it can neither be created nor destroyed. The total energy before and after the transformation remains the same.The lawof conservation of energy is valid inall situations and for all kinds of transformations. Thus during motion the sum of the potential energy and kinetic energy of the object would be the same at all points. That is, potential energy + kinetic energy = constant.Andcalled as mechanical energy.
(i) Which of the energy conversion occur in electric iron?
$(a)$ Electric energy converted into heat energy
$(b)$ Electric energy converted into light energy
$(c)$ Heat energy converted into electrical energy>
$(d)$ None of these
(ii) When ball drops from height which of the energy conversion takes place
$(a)$ Gravitational potential energy converted into kinetic energy
$(b)$ Kinetic energy converted into Gravitational potential energy
$(c)$ Heat energy converted into electrical energy
$(d)$ None of these
(iii) When ball is thrown vertically upward which of the following quantity remains constant?
$(a)$ Energy
$(b)$ Force
$(c)$ Potential energy
$(d)$ None of these
(iv) State law of conservation of energy.
(v) In hydroelectric power plant which energy conversion happens?

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Rutherford $(1871-1937)$ was known as the ‘Father’ of nuclear physics. He is famous for his work on radioactivity and the discovery of the nucleus of an atom with the gold foil experiment. Ernest Rutherford was interested in knowing how the electrons are arranged within an atom. Rutherford designed an experiment for this. In this experiment, fast moving alpha $(\alpha )$-particles were made to fall on a thin gold foil. On the basis of his experiment, Rutherford put forward the nuclear model of an atom, which had the following features:

There is a positively charged centre in an atom called the nucleus. Nearly all the mass of an atom resides in the nucleus.
The electrons revolve around the nucleus in circular paths.
The size of the nucleus is very small as compared to the size of the atom.

Drawbacks of Rutherford’s model of the atom: The revolution of the electron in a circular orbit is not expected to be stable. Any particle in a circular orbit would undergo acceleration. During acceleration, charged particles would radiate energy. Thus, the revolving electron would lose energy and finally fall into the nucleus. If this were so, the atom should be highly unstable and hence matter would not exist in the form that we know. We know that atoms are quite stable.
(1) Which of the following scientist was known as the ‘Father of nuclear physics?
$(a)$ $J.J.$ Thomson
$(b)$ John Dalton
$(c)$ $E.$ Rutherford
$(d)$ Neilsbhore
(2) Positively charged centre in an atom is termed as
$(a)$ Nucleus
$(b)$ Molecule
$(c)$ Atom
$(d)$ Protons
(3) Identify the correct statement
Statement $1$ – Positively charged centre in an atom called the nucleus.
Statement $2$ – The electrons revolve around the nucleus in circular paths.
Statement $3$ – Nearly all the mass of an atom resides in the nucleus.
Statement $4$ – The size of the nucleus is very small as compared to the size of the atom.
$(a)$ Only $2$
$(b)$ Both $3$ & $4$
$(c)$ Both $1$ & $2$
$(d)$ All of the above
(4) Write the features of Rutherford’s nuclear model of an atom?
(5) Define Nucleus.

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$100 \ ml$ of water at room temperature of $25^{\circ} C$ is taken in a beaker and a little of solid $S$ is dissolved in it by stirring to obtain a solution $X$ . More and more of solid $S$ is added to the solution with constant stirring, while keeping the temperature of solution constant at $30^{\circ} C$. After some time it is observed that no more solid dissolves in water and at the same time some solid is also left undissolved at the bottom of the beaker. The contents of beaker are filtered through a filter paper to obtain solution $Y$ in the form of a filtrate.
a. What name is given to solutions like $X ?$
b. What name is given to solution like $Y ?$
c. What will you observe if the solution $Y$ at $30^{\circ} C$ is cooled down to $10^{\circ} C$ by keeping the beaker in crushed ice? Why?
d. What term is used to denote the amount of solid dissolved in $100$ grams of water in a solution like $Y ?$

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Do we always need to heat or change pressure for changing the state of matter? Can you quote some examples from everyday life where change of state from liquid to vapour takes place without the liquid reaching the boiling point? In the case of liquids, a small fraction of particles at the surface, having higher kinetic energy, is able to break away from the forces of attraction of other particles and gets converted into vapour. This phenomenon of change of a liquid into vapors at any temperature below its boiling point is called evaporation.
$i.)$ Evaporation of liquid takes place at
$a.)$ Boiling point
$b.)$ Above boiling point
$c.)$ Below boiling point
$d.)$ None of these
$ii.)$ Evaporation takes place at surface of liquid because
$a.)$ They are heavy as compare to other particles
$b.)$ They have sufficient kinetic energy to break the force
$c.)$ They are light weight as compare to other particles
$d.)$ None of these
$iii.)$ During evaporation particles of liquid change into vapour
$a.)$ From the surface
$b.)$ From the bottom
$c.)$ From all over the liquid
$d.)$ None of these
$iv.)$ Define evaporation.
$v.)$ Explain process of evaporation

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