Partial Solution
EVERYDAY SCIENCE PAPER 1999
Note: Attempt TEN questions. All questions carry equal marks.
1. Discuss in brief, the contribution of Muslim scientists in the field of biological science.
2. Describe, in precise statements, various instruments which are being used in exploring the universe.
The universe can be explored by astronomical instruments called telescopes, and by space probes sent from earth to other planets. When using telescopes astronomers try to look at the energy being produced by the universe not just in the visible part of the spectrum (where our eyes can see) but at the whole range of electromagnetic radiation. We thus have radio telescopes, infrared telescopes, X-ray telescopes and even some telescopes that are burried deep underground looking for neutrinos.
Various Instruments
The most notable Universe exploring instruments may be as follows
1- The Hubble Space Telescope (HST)
The Hubble Space Telescope (HST) is a telescope in orbit around the Earth, named after astronomer Edwin Hubble. Its position outside the Earth's atmosphere provides significant advantages over ground-based telescopes — images are not blurred by the atmosphere, there is no background from light scattered by the air, and the Hubble can observe ultra-violet light that is normally absorbed by the ozone layer in observations made from Earth. Since its launch in 1990, it has become one of the most important instruments in the history of astronomy. With it, astronomers have made many observations leading to breakthroughs in astrophysics. Hubble's Ultra Deep Field is the most sensitive astronomical optical image ever taken.
2- Wilkinson Microwave Anisotropy Probe (WMAP)
The Wilkinson Microwave Anisotropy Probe (WMAP) is a NASA satellite mission led by Professor Charles L. Bennett of Johns Hopkins University, whose mission is to survey the sky to measure the temperature of the radiant heat left over from the Big Bang. The satellite was launched by a Delta II rocket on June 30, 2001, at 3:46 p.m. EDT from Cape Canaveral Air Force Station, Florida, USA
3. Explain the Solar System and the unifying characteristics which the Sun and its planets have.
4. How the solar and lunar eclipses are caused?
5. What is Ozonoshpere? Discuss the human technologies which are causing its depletion. What harm to man this depletive state would cause?
Ozonosphere
A layer in the stratosphere (at approximately 20 miles) that contains a concentration of ozone sufficient to block most ultraviolet radiation from the sun
The ozone layer is a layer in Earth's atmosphere which contains relatively high concentrations of ozone (O3). This layer absorbs 97-99% of the sun's high frequency ultraviolet light which is potentially damaging to life on Earth. Over 90% of ozone in earth's atmosphere is present here. "Relatively high" means a few parts per million—much higher than the concentrations in the lower atmosphere but still small compared to the main components of the atmosphere. It is mainly located in the lower portion of the stratosphere from approximately 15 km to 35 km above Earth's surface, though the thickness varies seasonally and geographically.
The ozone layer was discovered in 1913 by the French physicists Charles Fabry and Henri Buisson. Its properties were explored in detail by the British meteorologist G. M. B. Dobson, who developed a simple spectrophotometer that could be used to measure stratospheric ozone from the ground. Between 1928 and 1958 Dobson established a worldwide network of ozone monitoring stations which continues to operate today. The "Dobson unit", a convenient measure of the total amount of ozone in a column overhead, is named in his honor.
Depletion of the ozone
Only a few factors combine to create the problem of ozone layer depletion. The production and emission of CFCs, chlorofluorocarbons, is by far the leading cause.
Many countries have called for the end of CFC production because only a few produce the chemical. However, those industries that do use CFCs do not want to discontinue usage of this highly valuable industrial chemical.
CFCs are used in industry in a variety of ways and have been amazingly useful in many products. Discovered in the 1930s by American chemist Thomas Midgley, CFCs came to be used in refrigerators, home insulation, plastic foam, and throwaway food containers.
Only later did people realize the disaster CFCs caused in the stratosphere. There, the chlorine atom is removed from the CFC and attracts one of the three oxygen atoms in the ozone molecule. The process continues, and a single chlorine atom can destroy over 100,000 molecules of ozone.
In 1974, Sherwood Rowland and Mario Molina followed the path of CFCs. Their research proved that CFCs were entering the atmosphere, and they concluded that 99% of all CFC molecules would end up in the stratosphere.
Only in 1984, when the ozone layer hole was discovered over Antarctica, was the proof truly conclusive. At that point, it was hard to question the destructive capabilities of CFCs.
Even if CFCs were banned, problems would remain. There would still be no way to remove the CFCs that are now present in the environment. Clearly though, something must be done to limit this international problem in the future.
Harm to the Humanity
Even minor problems of ozone depletion can have major effects. Every time even a small amount of the ozone layer is lost, more ultraviolet light from the sun can reach the Earth.
Every time 1% of the ozone layer is depleted, 2% more UV-B is able to reach the surface of the planet. UV-B increase is one of the most harmful consequences of ozone depletion because it can cause skin cancer.
The increased cancer levels caused by exposure to this ultraviolet light could be enormous. The EPA estimates that 60 million Americans born by the year 2075 will get skin cancer because of ozone depletion. About one million of these people will die.
In addition to cancer, some research shows that a decreased ozone layer will increase rates of malaria and other infectious diseases. According to the EPA, 17 million more cases of cataracts can also be expected.
The environment will also be negatively affected by ozone depletion. The life cycles of plants will change, disrupting the food chain. Effects on animals will also be severe, and are very difficult to foresee.
Oceans will be hit hard as well. The most basic microscopic organisms such as plankton may not be able to survive. If that happened, it would mean that all of the other animals that are above plankton in the food chain would also die out. Other ecosystems such as forests and deserts will also be harmed.
The planet's climate could also be affected by depletion of the ozone layer. Wind patterns could change, resulting in climatic changes throughout the world.
6. Describe the principle and make up of a Television.
Almost all TVs in use today rely on a device known as the
cathode ray tube, or
CRT, to display their images. In a cathode ray tube, the "cathode" is a heated filament (not unlike the filament in a normal light bulb). The heated filament is in a vacuum created inside a glass "tube." The "ray" is a stream of electrons that naturally pour off a heated cathode into the vacuum.
Electrons are negative. The anode is positive, so it attracts the electrons pouring off the cathode. In a TV's cathode ray tube, the stream of electrons is focused by a focusing anode into a tight beam and then accelerated by an accelerating anode. This tight, high-speed beam of electrons flies through the vacuum in the tube and hits the flat screen at the other end of the tube. This screen is coated with phosphor, which glows when struck by the beam.
7. What is escape velocity? How the Satellites are launched and what are their uses?
Escape Velocity
In physics, escape velocity is the speed where the kinetic energy of an object is equal in magnitude to its potential energy in a gravitational field. It is commonly described as the speed needed to "break free" from a gravitational field. On the surface of the Earth, the escape velocity is about 11.2 kilometers per second
How are satellites launched?
Most satellites are sent into orbit either on rockets or expendable launch vehicles, which fall into the ocean once they've used up all their fuel. Some, such as the Hubble Space Telescope, are launched via the USA's Space Shuttle which returns to Earth after each mission and is reused.
The trick when launching a satellite is to get it high enough to do its job without losing the capsule to outer space. It's a delicate balance of push and pull, accomplished by the inertia of the moving object and the Earth's gravity. If you launch a satellite at 17,000 mph, the forward momentum will balance gravity, and it will circle the earth. On the other hand, if the satellite is launched faster then 23,500 mph, it will leave the gravitational pull of the Earth.
Why does a satellite stay in orbit?
Due to the balance of two factors:
1. velocity, or the speed at which it would travel in a straight line, and
2. the gravitational pull between the Earth and the satellite.
Satellites are used almost every day by everyone. Even though you can't see it, there will probably be one traveling above you today. Satellites are used for many things such as communication, oceanography, astronomy, surveillance, and a variety of other things as well . They help many scientists get a perceptive view at all kinds of objects anywhere in the world.
8. Explain Earthquakes and volcanoes. How volcanoes help in the formation of earth crust?
9. How characters are transmitted from parents to offspring?
10. Describe the function of kidneys in the human body.
11. What are the deficiency effects of the following nutrients in the human body?
a) Iron
Iron Deficiency Anemia
b) Iodine
Goiter
c) Fluoride
May cause increased dental caries and possibly osteoporosis
d) Vitamin A
Vitamin A is essential for night vision and improves effectiveness of the immune system. Its deficiency also causes retarded growth, Night blindness and susceptibility to infection. It can be found in many dairy products, and especially in carrots.
e) Vitamin D
Essential part of the diet required in the absorption of minerals in food, where a lack of vitamin D in the diet leads to a condition called rickets, where softening of the bones cause them to bend from the lack of calcium. Its deficiency also causes osteomalacia in the adults. Humans have the ability to synthesize vitamin D from sunlight.
12. What are the constituents of human blood and their characteristics?
13. Differentiate between
a) Neuron and neutron
b) Meiosis and mitosis
c) Heavy water and hard water
d) Climate and weather
e) Isotopes and isobars
14. Fill in the blanks
a) Plant cells manufacture their food due to the presence of ____________ (chlorophyll, vacuole, cell wall)
b) The mitochondria in a cell are the constituent of the ____________ (nucleus, cytoplasm, cell membrane)
c) Mitosis is a type of cell division wherein the number of chromosomes in the daughter cell is the ____________ (same, half, double)
d) Blood cells are of ____________ types (two, three, four)
Platelet is actually a fragment of the large bone marrow cells known as megakaryocytes
e) The ____________ causes sunburn and suntan (ultraviolet rays, alpha particles, gama radiation)
15. Which of the following statements are false or true. Write only true of false in the answer book. Do not reproduce the questions.
a) Xylem and Phloem are conducting tissues. (True)
b) Carbohydrates are cheapest and most ready source of energy. (True)
c) Enzymes are responsible for chemical digestion of food. (True)
d) Plasma is the fluid part of the blood in which the cells are suspended. (True).
e) Hemoglobin combines with oxygen and transport to different cells of the body. (True)
f) Neutron is the negative charged particles in an atom. (False)
g) Helium is the lightest gas. (True)
h) Venus is the smallest planet of the solar system. (False)
i) Image of an object is formed on the retina of the eye. (True)
j) Barometer is used for measuring the current. (False)
Disclaimer
This material is intended, but not promised or guaranteed to be accurate
I have only used "featured" or "protected" articles from Wikipedia (if they are used)
Aspirants are advised not to rely on the solution and use it for revision purpose only
I will try my best to post a paper each day till we reach the final 2009 paper