### ## PHYSICS EXPERIMENTS

discover everything from nature.....

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### ## knowledge is power

develop scientific approach...

### ## dream big

learning is continuous process....

### inspire yourself and inspire others

develop concepts....

### LEARNING BY DOING

combine experiments and theory....

## Stephen William Hawking....great Mathematician, Physicist

Prof. Stephen william Hawking was born on 8th Jan. 1942, in Oxford, England.  Stephen studied at St. Albans School.  Stephen was awarded Ph.D. titled "properties of Expanding Universe" in 1965.  Stephen William Hawking  was an English theoretical Physicist and Cosmlogist.

### Important Concept from Stephen William Hawking.......

This is the black body radiation which is supposed to be released by blackholes due to Quantum effects.  This leads to black hole evaporation, the meaning is, Hawking radiation reduces the mass and energy of blackholes.

AWARDS :

1. The Adams Prize: The prize is named after the mathematician "John Conch Adams"

2. Eddington Medal: Royal Astronomical society awards the Eddington Medal.

3. Fundamental Physics Prize: It is awarded by Fundamental Physics Prize Foundation

### TOP BOOKS WRITTEN BY STEPHEN WILLIAM HAWKING:

"A Briefer history of time" a famous book written by Stephen Hawking.  A Briefer history of time books gives explanation on all the forces of physics.

Another book - "The Universe in a Nutshell".

Stephen is a fellow of the Royal society and he is a member of the US National academy of Science.

## What is a Lens?

A transparent medium bounded by two surfaces, at least one of the surface should be a curved, is said to be a lens and it is said to be THIN LENS, When there is a small gap between the two surfaces or lenses where the thickness are much less and considered negligible in comparison to the radius of curvature.

When a lens of refractive index n2 is placed in the medium of refractive index n1, and the radii of curvatures of lens are R1 and R2, then we can write

( n1/v)-(n1/u)  =  (n2-n1)[1/R1  -  1/R2]

dividing the equation by n1,

we get,   1/v  -  1/u  =  (n2/n1  - 1)[1/R1 - 1/R2]

when the object is at infinity, u = infinity,  and then the image distance v = f, then

lens maker's formula is    1/f = (n2/n1  - 1)[1/R1 - 1/R2]

1/f =(n-1)[1/R1 - 1/R2]

LIMITATIONS OF LENS MAKER'S FORMULA :

- the lens should be thin to consider above formula and the medium is same on either side of the lens.

sign conventions:

for convex lens:

R1 is positive,  R2 is negative and f is positive

for concave lens:

R1 is negative, R2 is positive and f is negative

### PROBLEMS USING LENS FORMULA:

1. An object is placed at 8 cm from a lens of  focal length 15 cm, then calculate the image distance and determine whether the image is real or virtual.

2. A student using a lens of focal length -15cm, and object is placed at 20 cm from it, then calculate how far the image is from the lens and find out the magnification.  Conclude whether the image is real or virtual.

3. Calculate the image distance and determine whether the image is real or virtual when an object is placed at 20 cm, from a lens of negative focal length -10cm.

## Tuesday, 6 March 2018

### What is net neutrality?

NET NEUTRALITY.........

## PROBLEMS IN PHYSICS - REFLECTION AT CURVED SURFACES

PROBLEM 1:

Where is the image formed when 8 cm tall object is placed at 20 cm. in front of a concave mirror with focal length 5 cm.  Find out the size of the image also.

PROBLEM 2:

A 10 cm tall object is placed in front of a convex mirror of focal length 15 cm, Find out the image distance and write its characteristics .

PROBLEM 3:

10 cm focal length concave mirror is placed at 40 cm, from a wall.  Calculate the object distance such that its image is formed on the wall.

PROBLEM 4:

In front of 15 cm focal length concave mirror, an object is placed at 30 cm, if the object is displaced through 10 cm towards mirror, calculate by how much distance the image is displaced?

PROBLEM 5:

The image is formed behind the mirror, at a distance of 10 cm, when an object is placed at 20 cm in front of it.  Identify the type of mirror used and also calculate the focal length.

## IMPORTANCE OF TULSI LEAVES....

Tulsi is very important and most prominent herbs in the society.  We use to call the tulsi as 'king of herbs'.  The scientific name of the tulsi is 'ocimum tenuiflorum'.  Tulsi has been cultivated for more than 6000 years.  It is mostly used in Southeast asian countries. Tulsi plant can protect us from many infections.  Let us look at the health benefits of tulsi...

1. ORAL HEALTH:

Tulsi acts as very good mouthwash which can control oral plaque since it has very high antibacterial activity.

2. USEFUL TO PREVENT EYE DISORDERS:

Tulsi leaves protect the eye from free radiacals and environmental damage.

3. VERY GOOD FOR PROTECTING BLOOD VESSELS

Tulsi leaves possess antiinflmmatory and antioxidant properties, it can remove plaque in blood vessels.

4. TULSI CAN INCREASE IMMUNITY

Respiratory disorders like asthma can be treated using tulsi.

5. LIVER CAN BE PROTECTED

6. BLOOD SUGAR LEVELS CAN BE REGULATED

Tulsi can support blood sugar regulation by increasing insulin secretions in type2 diabetes people.

7. PREVENTS KIDNEY STONES

Tulsi helps to reduce uric acid level in the body, it has the property to to clean out the kidneys.

8. SKIN CARE

By consuming tulsi, one can be free skin from all infectios.

9. TULSI PREVENTS PREMATURE AGING

The free radical damage can be reduced by tulsi.

10. EFFECTIVE TO CURE COUGH AND COLD.

Tulsi is considered a sacred plant and it is also used as antiinflammatory and stress reducer.

## About Chandrasekhara Venkata Raman (1888-1970)

C.V. Raman was born on Nov.7, 1888 in Trichiopoly (Tiruchirapalli). The Raman's family lived on a low income when Raman was born.  C.V. Raman was awarded both Bachelor and Master's degree before Raman turned 20.

Why National Science Day is celebrated on Feb.28th?

In India, National science day was celebrated first on Feb.28, 1987.  Then onwards we are celebrating National Science Day on Feb.28, this is to mark the discovery on the "Raman Effect" by Indian Physicist, sir C.V. Raman on 28 Feb. 1928.

### What is Raman Effect?

While C.V. Raman travelling to Europe in the early 1920s, he noticed that the sea water is in blue color.  This leads to the discovery of the Raman Effect.

Definitions:

I. Change in the wavelength of light that occurs when a light beam is deflected by molecules.

II. Certain molecules cause waves radiation to scatter differently than the other molecules.

III. Raman effect is an inelastic scattering of photon.  Change in the wavelength of light that occurs when a light beam is deflected by molecules.  During  scattering, a very few photons undergo a change in behaviour.
Experiment: When there is an interaction between the particles of  the liquid and the photons to be responsible for the change in the behaviour of the photons.

Why National science day is celebrated on Feb.28?

In India, the first National science day was celebrated on Feb. 28, 1987, then onwards continuously celebrating National science day.  The reason behind it is that to mark the discovery of the "Raman Effect" by Indian physicist sir C.V. Raman on 28 Feb. 1928.

Applications of Raman Effect:

I. NON-DESTRUCTIVE TESTING:
Scientists using the raman effect for analysing the atomic structures of the particles without causing any destruction to the substance.

II. Raman effect - Raman spectroscopy is being used to study the properties of different materials.

III. The chemical constitution of the substances also can be analysed by Raman effect.

### DAILY LIFE EXAMPLES:

Why the sky is blue?

As we all know that when light travels in a straight light, and something gets in its path - that may reflect the light, bend it, or scatter it.  By using these known properties we can explain it.

When sunlight passes through the atmosphere, due to the gases & particles present in air, the light is scattered in all the directions.  Sunlight is combination of seven colors, among them, blue is scattered more than the other colors because it travels as shorter and smaller waves.  Blue color is reached to our eyes from all the directions, that is most of the time we see a blue sky.

## Getting started with LibreOffice Calc

What is LibreOffice Calc?  Calc is the spreadsheet component of LibreOffice, generally we use data which is entered in a spreadsheet and then it can be manipulated, to produce required results.  In LibreOffice Calc, one can use different Functions to perform mathematical based calculations, the main advantage of it is, we can convert calc file into different types of files like HTML, pdf, etc.
introduction:
Calc consists of spreadsheets, each spreadsheet is divided into various individual sheets, each sheet consists of cells.  To identify a cell, we should take its row number and column letter.  Each sheet consists of rows and columns.
parts of the Calc:

1) title bar:  The name of the current spreadsheet.  If it is a new spreadsheet, the name would be untitled X.
2) Menu bar:  It is after the title bar, sub menus will appear in a menu, when we click on it.  The menu bar menus are...File, Edit, View, Insert, Format, Tools, Data, Window, Help, ..
3) tool bar:

## IMPORTANCE OF PROTEIN:

Copy code snippet Throughout every stage in life, our body needs a healthy balance of protein.  Children needs protein for growth and development, adults use protein to build new tissues and to decrease the effects of stress.  Elderly require protein for muscle tone and to have good health.  Protein is the basic building block for muscles and every body components.  Protein provides energy.

Which is the best protein source?

- A high quality protein source is soy protein isolate.  Our body does not prepare all amino acids, we have to consume 9 essential acids from food only.  A protein in food, should provide all 9 essential amino acids.

- protein rich foods should have low fat.

- any product of protein source should have a PDCAAS score of 1

Who needs protein?

- to get all 9 essential amino acids

- who does not drink adequate amounts of milk, and other low fat protein sources etc.

- pregnant and lactating women should consume more protein.

### subject on amino acids

Amino acids are the building blocks of proteins.  Proteins are the long chains of amino acids. Proteins are necessary for staying healthy and alive.  Our human body has thousands of different proteins.  Each amino acid consists, a central carbon atom, an amino group, a carboxyl group, and an R group.  Each amino acid is unique depends on R group. Amino acids are alanine, arginine, asparagine, aspartic acid, cystein, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan,  tyrosine, valine.  There are two types of amino acids, they are essential and non-essential amino acids.  One should get essential amino acids from food only our body cannot synthesize these.

### uses of protein

Protein is a macronutrient, which tells us that our needs relatively large amounts of protein.  Vitamins and minerals are micro nutrients which are needed in small quantities they are called micro nutrients.  Our body does not store protein.  Hair and nails are mostly made of protein.  Our body uses the proteins to repair and build tissues.  Proteins helps in making enzymes, hormones, and other body chemicals.  Protein is an important building block of skin, blood, cartilage and bones and muscles. Protein helps in maintaining weight.   Protein is called building block of the body.  Protein helps for the maintenance of the body tissue.  Protein helps in creating harmones.  A small protein, insulin, that regulates the blood sugar.  Proteins also helps in digestion. Secretin a protein harmone helps in digestion.

Enzymes:  Without enzymes most of the chemical reactions efficiently proceed in the body.  Enzymes increase the rate of chemical reactions.

Haemoglobin is a protein that transports oxygen throughout the body.Protein also acts as antibody.  Which prevents infection, illness.  It destroys bacteria and viruses.

### protein deficiency:

Protein rich foods should be consumed adequately since our body does not store protein.  General symptoms are fluid retention, anemia, shrinkage of muscular tisses, increase blood pressure, slow to heal, menstrual cycle is irregular, poor concentration, poor sleep, high cholesterol, hair breakage and hair loss, etc.