Q. & A.s SCIENCE & TECHNOLOGY -- 1

Q. A.s  ‑‑‑  SCIENCE  & TECHNOLOGY -- 1

1.   How is it possible to transmit a number of channels through the same cable?

Transmitting a number of channels through the same cable is possible because of frequency division multiplexing. Any signal can be broken down into sine wave components of different magnitude and frequencies called harmonics which when added together result in the original signal.

2.   When a vehicle passes a flickering can be seen on TV. Why?

From the spark plug sparks of em energy is released. This disturbs the TV signals. That is why the flickering.

3.  How do blotting paper and tissue paper differ from ordinary paper?

The absorbent property is due to the presence of more microscopic capillaries, which exhibit more capillary action resulting in the easy entry and spreading of any liquid which come in to contact.

The ordinary writing paper is impregnated with sizing and coating materials. This prevents the absorbing property because all the microscopic pores are closed. For manufacturing this paper polyvinyl alcohol, carboxyl methyl cellulose, alginates and certain wax emulsions in combination with starch ar also used as loading agents for the manufacture of these papers.

4.  Why arctic ice came to record low?

The Arctic ice covers an area of 1.58 million sq. miles. In August 2012 1,00,000 sq. miles of sea ice a day disappeared. It is due to global warming.

5.  Ripened mangoes smell very strong. Why?

Chlorophyll is broken down.

New pigments formed change the colour of the skin.

Acids are broken so the fruit becomes from sour to sweet.

The starch is digested by amylase to produce the simple sweet sugars.

Enzymes breakdown large organic molecules into smaller ones that can be volatile.

This volatile substance gives aroma.

High level ethylene is produced to indicate that the fruit is ripened.

6.  What happens to the minerals and vitamins of milk when we prepare tea?

Boiling at 100 ⁰C changes the constituents of milk. The higher the temperature the greater will be the changes. The longer the exposure time to heat the more changes take place in milk.

Milk is a source of Vit. A, Vit. D, Vit. C and B-complex.

Milk is a major source of calcium [1200 mg/lit].

7.   What is a sea glider?

It is an autonomous probe designed to map underwater weather systems.

It can stay under water for months together at a time.

A computer adjusts its course using GPS.

The batteries can last for 40 days.

8.   What are the advantages of LPG in automobiles?

It is as safe as any other fuel.

It is cost effective.

It is clean.

It is pollution less fuel.

9.   What is SASER?

SASER stands for Sound Amplification by Stimulated Emission of Radiation. Phonons work like photons. SASERs work as LASERs. Phonons are high frequency sound waves.

10. How do microwave ovens work?

The wave length is generally 0.3 to 30 Cms.

The frequency is 1 – 100 GHz.

This radiation penetrates deep into the molecules. The vibration causes heat generation.

Traditional heating systems heat only the surface.

This microwaves heat the whole object.

11.    What material vessels  are used in microwave ovens?

China clay, glass, plastic, paper, cardboard,…

12. What is Mask for Molecules ?

In a substance some molecules are masked while some others are repaired or modified.

Enzyme molecules in living cells sometimes effect exquisitely delicate chemical transformations of other molecules using the same masking principle.

13. How can a robot that can walk on water work?

China invented this. Qinmin Pan and his colleagues created it. Using porous, super water repellent nicket foam to fabricate the three supporting and two jimping legs the group made a robot that could leap more than 5.5 inches, it can jump 14 inches forward. It can walk on water at 3.6 miles per hour.

14. Why do we feel numbness in our legs when we sit down for a long time?

Numbness is also called “limb falling sleep”

It is also called paresthesias.

It is due to temporarily reduced supply of blood to limbs.

Secondly if there is cholesterol in the body.

Thirdly abnormal levels of calcium, potassium, or sodium  present in the body.

Fourthly Vit. B 12 deficiency.

Fifthly diabetes.

15.   What are the differences between distilled water and sterile water?

Distilled water is pure H₂O. If we boil water to kill all the germs it is called sterile water. Generally distilled water is used in giving injections, doing experiments in chemistry labs. If such water is not available while giving injection, sterile water can be used.

16.   Why do we swing our arms while moving?

Arms act as mass dampers while walking or running.

It is the movement of quadrupeds. It indicates that the primates of human beings were quadrupeds.

17.    What is the role of flashes in the atmosphere?

Each flash produces 150 lakh tons of Nitrogenoxide. It produces 36 kilo amperes of current. Every second all over the nearly 100 flashes per sec appear.

18.    How are diamonds ground?

Diamonds are cut by robots using laser beams.  This robot was created by Ananda Sivam Krishna Pillai of Sri Lanka. This robot has artificial intelligence. It sends low power laser and studies in thousands of ways of cutting the diamond given to it. It brings out the best size from that diamond.

19.    Why can’t snake poison kill a mongoose?

Firstly Mongoose is faster than the movement of a snake.

Secondly the snake poison contains alpha neurotoxins which do not cause any effect on mongoose. It is because they are neutralised.

20.    What is ultracision?

It is knife that vibrates at 55,000 hertz. When a patient is operated he cannot understand pain and blood also clots fast.

21.    Why people who smoke look older than their age?

The skin of the smokers is 40% thinner than non-smokers. That is why they look older.

22.    How does a transistor radio work?

Electromagnetic energy travels at the speed of light. Sound travels at 331 mps. To send voice signal to remote parts of the globe it is imposed on em energy. This called modulation. After modulation it is sent into space. The receiving station receives the signal and demodulates it to separate em signal from audio signal. Audio signal goes to speaker.

23.    What is “green rust”?

It is a rare kind of iron mineral.

It used to scrape toxic metals and radioactive species from the environment.

It also played  a crucial role in the creation of our early atmosphere.

It is recently found in Indonesia, Lake Matano.

It scavenges dissolved nickel, a key micronutrient for methanogenesis.

24.    Why do old earthen pots lose their efficiency to keep water cool?

Potable water is  not pure water. It contains some minerals such as K, Na, Mg, Ca salts suspended particles dissolved oxygen and carbon dioxide etc. among others.

During the course of usage some of these calcium and magnesium ions in water tend to precipitate as insoluble carbonates and sulphates which gradually plug and pores and channels of the pot walls.

25.    What is Higg’s Boson Particle?

It is the particle responsible for the creation  of the universe.

It is the particle responsible for atoms to have mass.

Without this nothing will be there.

More than 100 scientist of India participated.

The research centres participated are

1.       Saha Institute of Nuclear Physics, Calcutta

2.       Tata institute of fundamental research, Bombay

3.        Harishchandra Research institute, Alahabad

4.       Bhuvaneswar Institute of Physics