An earthen pot (matka) has many small pores. Water seeps out through them and evaporates from the surface of the pot. The energy needed for evaporation is taken from the water kept in the earthen pot. As a result, water kept in earthen pot becomes cool.

In mathematics, graph theory is the study of graphs, which are mathematical structures used to model pairwise relations between objects. A graph in this context is made up of vertices (also called nodes or points) which are connected by edges (also called links or lines). Graph theory is also widely used in sociology as a way, for example, to measure actors' prestige or to explore rumor spreading, notably through the use of social network analysis software. Under the umbrella of social networks are many different types of graphs.

Animals that eat their own kind are also examples of cannibalism. People who engage in cannibalism are called cannibals. Cannibalism is the act of consuming another individual of the same species as food. Cannibalism is a common ecological interaction in the animal kingdom and has been recorded in more than 1,500 species. Human cannibalism is well documented, both in ancient and in recent times.

The term “vacuole” means “empty space”.  They help in the storage and disposal of various substances. They can store food or other nutrients required by a cell to survive. They also store waste products and prevent the entire cell from contamination.

The plant cells have larger vacuoles because they require more water, organic and inorganic components for the proper functioning of the cell.

The term “vacuole” means “empty space”.  They help in the storage and disposal of various substances. They can store food or other nutrients required by a cell to survive. They also store waste products and prevent the entire cell from contamination.

The plant cells have larger vacuoles because they require more water, organic and inorganic components for the proper functioning of the cell.

As Earth rotates, the Moon's gravity causes the oceans to seem to rise and fall. (The Sun also does this, but not as much.) There is a little bit of friction between the tides and the turning Earth, causing the rotation to slow down just a little. As Earth slows, it lets the Moon creep away.

Centriole is a small, cylindrical cell organelle, seen near the nucleus in the cytoplasm of most eukaryotic cells. The main function of the centriole is to help with cell division in animal cells. The centrioles help in the formation of the spindle fibers that separate the chromosomes during cell division (mitosis).

Liquids are difficult to compress as particles have less space between them to move. Liquids have fixed volume but no fixed shape. The rate of diffusion in liquids is higher than that of solids. Force of attraction between the particles is weak than solids.

A)250°C : Gaseous state (as boiling temperature of water is 100°C)
b)100°C :since water boils at this temperature thus it can exist in both liquid and gaseous form. At this temperature, after getting the heat equal to the latent heat of vaporization, water starts changing from liquid state to gaseous state.

Uterus is also called the womb, the uterus is a hollow, pear-shaped organ located in a woman's lower abdomen, between the bladder and the rectum. Ovaries. Two female reproductive organs located in the pelvis. Functions of the uterus include nurturing the fertilized ovum that develops into the fetus and holding it till the baby is mature enough for birth. The fertilized ovum gets implanted into the endometrium and derives nourishment from blood vessels which develop exclusively for this purpose.

The incense stick releases the gas when it is lighted in one corner of the room . The molecules in the gas are in free state. There are large intermolecular spaces between the molecules of the gas. The gases are not rigid , they don't have definite shape . That's why they spread very quickly . Hence , the fragrance spreads in the whole room very quickly

The energy possessed by a body because of its position or configuration is known as potential energy.

The energy transferred to an object is stored as potential energy if it is not used to cause a change in the velocity or speed of the object. If we stretch a rubber band the energy transferred to the band is its potential energy. Work is also done while winding the key of a toy car. The energy transferred to the spring inside is stored as potential energy. The potential energy possessed by the object is the energy present in it by virtue of its position or configuration.

• Potential Energy of An Object At A Height:

Suppose a body of mass m is raised to a height h above the surface of the earth. The force acting on the body is the gravitational pull of the earth m x g which acts in the downward direction. To lift a body above the surface of the earth, we have to do work against this force of gravity.

Work done = Force x Distance

So, W = m x g x h

This work gets stored up in the body as potential energy.

Thus, potential energy = m x g x h

Where m is the mass of the body, g is acceleration due to gravity; h is the height of the body above the reference point.

• The  unstable  isotopes  which  emit  various  types  of  radiations  are  known  as  radioactive isotopes.

• The atoms of different elements having different atomic numbers but the same mass number are known as isobars.

• Bohr's Model of an Atom:

Niels Bohr, revised Rutherford’s atomic model and put forth the following suggestions:

Neils  Bohr  proposed  that  the  electrons  possess  a  specific  amount  of  energy which allows  them  to revolve around the nucleus. The electrons are confined to these energy levels.  While  revolving  in  these  discrete  orbits,  the electrons  do  not  radiate  energy.  Hence, these orbits  are  also  known  as stationary  orbits or stationary shells. Smaller the size of the orbit, smaller is its energy.

As we move away from nucleus, the energy of the orbit increases progressively. The  transfer  of  an  electron  from  one  orbit  to  another  is  always  accompanied  with  absorption  or emission of energy. When an electron jumps from a lower energy level to a higher energy level, it absorbs energy. When an electron returns from a higher energy level to a lower energy level, it emits energy.

According to the Newton's first law of motion the force is directly related to the change in momentum of a body, so

F = dp/dt

now momentum is given a. p = mv

where m is the mass and v is the velocity

so,

F = d(mv)/dt = m(dv/dt)

or we get

F = ma

Definition of one unit force

The movementum is defined as the product of its mass and velocity.

movementum = mass x velocity

or p = m x v

where p = movementum

m = mass (kg)

v = velocity (m/s)

SI unit is kg-m/s

The total momentum of the gun and bullet before firing is zero as both of them are at rest.

Newton's second law of motion gives the relationship between the force and acceleration.
The second law of motion states that
the rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of force

Medical applications

• Ultrasonic waves are used to capture the images of the heart and its features and problems associated with the heart, if any (for treatment purpose). This is called echocardiography.
• Ultrasound scans/Ultrasonography are very commonly used to get images of internal body organs such as liver, kidney, uterus. It helps the doctor to diagnose and treat problems in the body of the patient. In this method, ultrasound waves are made to travel through the body to the organ under consideration. They get reflected and these are converted to electrical signals which can be monitored on a screen.
• Ultrasonography is used to observe the growth of the fetus inside the uterus. It can also used to monitor the abnormalities.
• It is used to break kidney stones into fine grains which later get flushed out through urine.    

Industrial Applications

• Ultrasound is used to clean machine parts located in places which are not easily accesible - electronic components, internal parts, spiral parts etc. The objects are placed in a cleaning solution and waves are passed through it. Because of the high frequency of the waves, the dust particles just fall out.
• It is used to detect defects, flaws, cracks in machine parts, bridges, building etc. Ultrasound waves are passed at one end and monitored using detectors. If there are laws or cracks, then the ultrasound waves are reflected back indicating the presence of a defect.