Who was algebra named after?

The word algebra comes from the Arabic language (الجبر al-jabr "restoration") from the title of the book Ilm al-jabr wa'l-muḳābala by al-Khwarizmi. The word entered the English language during Late Middle English from either Spanish, Italian, or Medieval Latin.

How many times does a bee flap its wings in a second?

"In contrast to the fruit fly that has one eightieth the body size and flaps its wings 200 times each second, the much larger honeybee flaps its wings 230 times every second."

How long is the earth's circumference?

The circumference of Earth at the equator is about 24,902 miles (40,075 km), but from pole-to-pole — the meridional circumference — Earth is only 24,860 miles (40,008 km) around. This shape, caused by the flattening at the poles, is called an oblate spheroid.

Microscope Objective Lens Function

All parts of the microscope are important, but the objective lenses - the lower, magnifying lenses - must be treated with particular care. The lenses are of the best quality and need to be handled very carefully. Sometimes two lenses are glued together, and you must be careful not to use solvents such as strong alcohol solutions or acetone, which could dissolve the glue or cement.

Objectives are referred to by their magnifying power, which is marked on the side. The microscope you will use has the following objectives:


• x 10
• x 40
• x 100 (this objective is often called the oil immersion objective; sometimes it has a black or red ring around it for easy identification).

Objectives, showing working distance between front lens and specimen

The mechanical stage

The mechanical stage holds the slide secure and allows the specimen to be moved smoothly backwards, forwards or sideways. Sometimes a scale is fitted to two sides of the stage to show the extent of the movement. This is called the Vernier scale, and it is useful to know how to use it; it can be used to trace a part of the blood film that you need to re-examine or show to your supervisor.

Substage condenser (with iris diaphragm)

The substage condenser is made up of a number of lenses. These centre the light from the mirror, or electric light source, to a central spot on the field. The substage condenser can be raised or lowered to give maximum or minimum illumination.

Inside the condenser is the iris diaphragm. This is used to control the amount of light passing through the condenser. The iris diaphragm consists of a number of interlocking leaves made of a thin metal. It is adjusted by means of a lever.

Filter holder and blue filter

Beneath the iris diaphragm is the filter holder. This is where a blue filter is placed when you use an electric light source for illumination. It has the effect of making the microscope field white rather than yellow.

Microscope Diagram with Name

1. Main tube inclined head
2. Body tube (prism) inclined head
3. Revolving nosepiece
4. Objective
5. Stage (mechanical stage)
6. Substage condenser with iris diaphragm
7. Mirror
8. Base (foot)
9. Ocular (eyepiece)
10. Arm (limb)
11. Coarse adjustment
12. Fine adjustment

MICROSCOPE  INVENTION

Today, we'll explore the invention of the microscope. In biology class, it brought a whole new world into focus. The microscope gave us technology and a better quality of life.

So it's worth examining just how it came to be. Glass was invented about 22-hundred B-C. In the 1st century, Romans discovered if they made the glass thick in the middle and thin on the edges, objects viewed through it looked larger.

People started using lenses more toward the end of the 13th century when eye glasses were made. Magnifying glasses, the earliest of microscopes, came shortly thereafter.

It wasn't until 1590 when the forerunner to the modern microscope was invented. Two Dutch spectacle makers, Zaccharias Janssen and his son Hans found that the proper combination of lenses in a tube, made objects appear greatly enlarged. Their invention was the first compound microscope: which uses two or more lenses and is still in use today.

Galileo, the father of modern physics and astronomy, heard of these early studies. Through his own experiments, he harnessed the power of glass. In doing so, he designed a superior microscope that included a focusing knob.

Then, Anton van Leeuwenhoek, the father of microbiology, developed techniques to grind and polish glass. He made small lenses with great curvatures. With his lenses, his microscopes were able to magnify more than 200 times. He saw things never seen before: bacteria, yeast, blood cells and tiny animals swimming in a water drop.

Microscopes are now are so powerful, it's the equivalent of being able to see a penny on your football stadium seat from outer space. Microscopes continue to be a researcher's enduring partner bringing into focus tiny worlds we endeavor to understand.

Who really invented radio?

The history of radio technology is plagued by controversy over the question of who actually
invented the thing. The answer most often given is Italian inventor Guglielmo Marconi, but
many others made important discoveries that give them good claim to the title. Here’s a rundown on the contenders for the title of The Father of Radio:

✓ Marconi: He was the first person to demonstrate radio successfully and exploit it commercially.
In 1901, Marconi sent a message via radio across the Atlantic from England to Canada, though the message was faint, consisted of nothing but the letter S, and reception of the message wasn’t independently confirmed. Nevertheless, Marconi’s accomplishment was astonishing, and he
made many important contributions to the technology and business of radio
.
✓ Tesla: In 1943, the U.S. Supreme Court ruled that many of Marconi’s important radio patents were invalid because Nikola Tesla had already described the devices covered by Marconi’s patents. Tesla was a brilliant engineer who is best known for being the champion of alternating current over direct current for power distribution. He publicly demonstrated wireless communication devices as early as 1893. Tesla believed that wireless technology would be used not only for communication, but for power distribution as well.

✓ Lodge: In England, Sir Oliver Lodge was building wireless telegraph systems in the mid-1890s.

✓ Popov: In Russia, Alexander Stepanovich Popov was demonstrating wireless telegraph transmissions around the same time as Lodge.

✓ Bose: In India, Sir Jagadish Chandra Bose was also demonstrating wireless telegraph transmissions in the early 1890s. Whether these demonstrations occurred before, after, or at the same time as other demonstrations by Lodge, Popov, and others is under dispute.

✓ Many others: The list of names of others who did important research and made important  iscoveries in the last decades of the nineteenth century is long: Heinrich Hertz, Edouard Branly, Roberto de Moura, Ernest Rutherford, Ferdinand Braun, Julio Baviera, and Reginald Fessenden are just a few of the many individuals who made important contributions. So it seems that no one person has a clear-cut claim to being the first to invent radio. Work was being done all around the world and discoveries were being made it seems every day. It may be that the best answer is that no one
“invented” radio. Radio is a natural phenomenon. It was discovered, not invented. What was invented were ways to exploit the phenomenon of radio by building devices that could generate radio waves and modulate them to add information, as well as devices that could receive radio waves and extract theinformation that was added.

Understanding Radio Waves

Most people think of radio as wireless broadcast of sound, most often music and speech. But the term radio is actually much broader than that; the broadcast of sound is actually just one application of the extremely useful electrical phenomenon that is called radio. Radio takes advantage of one of the most interesting of all electrical phenomena: electromagnetic radiation (often abbreviated EMR), which is a type of energy that travels in waves at the speed of light. EMR travels freely through the air and even in the vacuum of space. EMR waves can oscillate at any imaginable frequency. The rate of the oscillation is measured in cycles per second, also known as hertz (abbreviated Hz). The term hertz here does not refer to the car rental company. Instead, it honors the great German physicist Heinrich Hertz, who was the first person to build a device that could create and detect radio waves. Radio is simply a specific range of frequencies of EMR waves. The low end of this range is just a few cycles per second, and the upper end is about 300 billion cycles per second (also known as gigahertz, abbreviated GHz.) That’s a pretty big range, but EMR waves with much higher frequencies exist as well, and are in fact commonplace. EMR waves with frequencies higher than radio waves go by various names, including infrared, ultraviolet, X-rays, gamma rays, and — most importantly — visible light. That’s right; what we call light is exactly the same thing as what we call radio, but at higher frequencies. The frequency of visible light is measured in billions of hertz, also called terahertz and abbreviated THz. The low end of visible light (red) is around 405THz and the upper end (violet) is around 790 THz

No.of ntoe books x	2	4	6	8	10	12
Cost (Rs y)	30	60	90	120	150	180

MODEL QUESTION PAPER ENGLISH – PAPER II

Class: X Time: 2.30 hrs
Max marks: 100

SECTION A –NON-DETAILED (35 MARKS)1. Fill in the blanks with the appropriate phrases given below to form a complete meaningful paragraph: [5x1=5]

Kumar watched (i) __________________ flying in a (ii)________________ and remembered the time when he had see (iii) ____________________ and his father had told him that the birds had come there to stay only (iv) _______ and would soon leave the (v) ____________ and return to their home in the Artic.

i) for a short while
ii) the migratory birds
iii) the place of their sojourn
iv) nestlings in Vedangthangal
v) streamlined ‘V’

2. Read the following sentences and identify the character speaker: [5 x 1 = 5]

i. “I will call you Goldy”.
ii. “I shall perform some magic tricks.”
iii. “Help! Save me from drowning.”
iv. “At least we could spend some time together.”
v. “I’ve been in search of a model to pose as Judas Iscariot.”

3) Match the following appropriately: [5 x 1 =5]

A) Judas     caught in a drain
B) Kumar     clever little boy
C) Mom    one of two figures for a painting
D) Celine   young and enterprising
E) Hubert    fond of playing the piano hid in the cupboard

4) Complete the following sentences choosing the correct answer from the options given below: [5 x1 = 5]

i) Mom allowed __________to keep the dog.
a) Goldy b) Shelly c) Sam d) Diane
ii) The brothers started off the ride with __________.
a) a thumbs up sign b) a wave of the fla
c) a whistle d) a gun shot
iii) There were _________ thieves hiding in the cupboard.
a) four b) six c) three d) five
iv) The painter was trying hard to find a model for a painting of……………
a) an artist b) Judas Iscariot c) a beggar d) a poet
v) Dad finally got an employment _________.
a) at a doctor’s clinic b) as a clerk
c) as a lecturer d) with an auditing firm

5) Read the passage given below and answer the questions that follow : [5 x 1 = 5]

With a shudder he once again turned to the window. The sky was dotted with birds flying in a streamlined ‘V’! They seemed to be hurrying, every one of them of one mind as if they had an important goal to pursue. It was that time of the year when the migratory birds were returning to their homes after a five - month warm sojourn. He remembered his childhood picnic with his parents to Vedanthangal, where he had seen flocks of birds nestled among the trees. Dad had hired a telescope to give him a closer view of the nest, where he saw tiny little nestlings-five of them! Dad had then told him that even though these families resided here, they would soon go back to their homes far in the cold regions of the planet. His father’s words rang clear in his ears “You see Kumar, though they have stayed here for almost half a year and have enjoyed our climate and the food available, they know that their home is in the Arctic. And there’s no place like home, is there?”

Kumar gazed at the flock flying home from where they had come. But slowly his vision blurred as tears filled his eyes. ‘Home is where the heart is’ Kumar thought, watching the birds till they were just specks on the distant horizon. Kumar left the room with a sure stride and a strong determination writ large on his countenance.

i. What was the ‘V’ shaped formation seen by Kumar?
ii. What did the flight remind him of ?
iii. Describe what Kumar had seen amidst the trees
while on his picnic.
iv. What behaviour among the birds taught Kumar of
the importance of ‘home’?
v. What do you think Kumar had decided to do? Give
a reason for your answer.

7) Answer in a paragraph any one of the following questions: [1x 5=5]

a) Narrate the story ‘The Face of Judas Iscariot’ in your own words
b) How did the close encounter result in bringing the brothers closer to each other?
c) Imagine you were Hubert and knew of the thieves’ plan to rob the house. How would you have dealt with the situation?

SECTION – B [LANGUAGE FUNCTIONS-15 MARKS]
II. [A] 1. Make notes of the following passage and
2. Prepare a summary using the notes. [5+5=10]

Thank you
Yours sincerely,
K.Ramesh
(SPL)