GOTW: Sciene and tech game

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rajnish kumar

@_rajnish_

Inactive

Posted: 16 years ago

***************** Science and Technology game********************

Hi friends here i present a game
this is a simple one. In this game one will ask simple questions and other will answer it related to science and technology. The person who will answer will gain 5 points if answered correctly and loose 2 if answered wrong 😉.the person who ask question will decide how much marks to be given in between 5 and -2 .The person while answering will have to put a question and let other try. Every person's points will be updated regularly.this will be played 4 2 weeks and so depending on participation and post. after the end of the game the person having maximum point will be winner😛

let me begin first

Q- What is the distance( in light yrs) between earth and sun?😃
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Edited by rajnish_here - 16 years ago

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Frequent Posters

akhl

@akhl

Dazzler

Posted: 16 years ago

In light year it will be very small. Let us calculate.

Distance between Earth and Sun = 150 million km = 150*10^6 km

1 light year = 9.46 * 10^12 km

Therefore distance in light year = (150*10^6)/(9.46 * 10^12) light year

= 15.8 * 10^-6 light year

= 1.58 * 10^-5 light year

Let us try another way: -

Light takes about 8.32 min to reach from Sun to Earth.

1 year = 365.25 days = 365.25 * 24 hours = 365.25 * 24 * 60 min

This means that light takes

(8.32)/(365.25 * 24 * 60) year

= 1.58 * 10^-5 year to reach from Sun to Earth.

Therefore distance between Earth and Sun = 1.58 * 10^-5 light year

Note: I have rounded off the numbers.

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Q - What is the definition of 1 meter?

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rajnish kumar

@_rajnish_

Inactive

Posted: 16 years ago

wow!!! avinash you have answered correctly👍🏼. Thanks for wonderful explanation😃

your answer is
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One meter is the length of the path traveled by light in vacuum during a time interval of 1/299 792 458 of a second.
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My next que
What is black hole? how it is formed?

Edited by rajnish_here - 16 years ago

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akhl

@akhl

Dazzler

Posted: 16 years ago

Your answer is correct. 5 points to you.
Are only we two here? Wish others too participate.
Let me answer your question. The topic of black hole is very vast. So, I will be brief.

A black hole is a region in space inside which gravity is so high nothing, not even electromagnetic radiation(e.g. light) escapes it. For every black-hole there is a boundary, which is called as event-horizon. Light can escape the gravitational pull of the black hole if it is outside the event horizon, but once it goes inside the event horizon, then it is not able to escape.

There is something called Hawking radiation. Black holes emit Hawking radiation. One may think that this radiation comes out of black-hole, so what I wrote above is wrong. But in reality, this radiation does not come from inside the event horizon. What happens is that virtual particle-antiparticle pair forms just outside the event horizon. If both particle and antiparticle remain outside the event horizon, then after a short time, they will meet and annihilate. But it is also possible that one of them will move towards the black hole and the other away from it. The first one goes inside the event horizon. So, the two of them do not annihilate and the second one now becomes a real particle. To an outside observer, it may look like the second one is coming from black hole. But, in reality, it comes from just outside the event horizon.

Another property of black hole is that to an outside observer it looks as if the time inside black-hole stands still.

Much more can be written about black holes, but as I said, I must be brief because it is such a vast topic.

Black-holes are formed in two ways. Most of black-holes are formed because of gravitational collapse of stars. Inside a star, there are two kinds of forces. One is gravitational force, which pulls the content of the star radially inward. The other is due to radiation pressure, which pushes the content of the star radially outward.
When the mass of the star is more than about 3 times the mass of the Sun, then radiation force is too weak to prevent gravitational collapse and the star goes on collapsing. Its density goes on increasing, its gravitational field goes on increasing and finally the star becomes a black hole. This about 3 times Sun's mass is as per theoretical calculations. This is the lower limit. So, mass of the star collapsing can be more than this. Most of real black-holes are formed by the collapse of the stars of at least 10 to 15 Sun's mass. Some are even millions of Sun's mass - called as super massive black holes.

There is another way by which black-holes are formed. Such black holes are called as primordial black holes. They are formed when very huge external pressure pushes the contents of a star inward and it pushes so hard that ultimately black hole is formed. At present, such huge pressure does not exist. But it is possible for the existence of such huge pressure shortly after Big Bang.
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How many bones does a new-born have?

Edited by akhl - 16 years ago

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rajnish kumar

@_rajnish_

Inactive

Posted: 16 years ago

well explained avinash😃 you got 5 point more
yeh even i wonder why not ppl are participating but i informed many of my I.F friends through P.M hope for more participation soon😛
well this is biology que my most week subject and the chance has come to loose marks but i will try😊
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the new born have more bone then adult. many of the bone of new born din't joint together and so if adult have 206 bone new born should have even more than this. I think number of bone new born have is approximately 270

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my next que

how does refrigerator works?

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Janaki

@RamKiSeeta

Achiever

+ 6

Posted: 16 years ago

Originally posted by: rajnish_here
well explained avinash😃 you got 5 point more
yeh even i wonder why not ppl are participating but i informed many of my I.F friends through P.M hope for more participation soon😛
well this is biology que my most week subject and the chance has come to loose marks but i will try😊
_____________________________________________________________________________________

the new born have more bone then adult. many of the bone of new born din't joint together and so if adult have 206 bone new born should have even more than this. I think number of bone new born have is approximately 270

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my next que

how does refrigerator works?

Sorry guys, but I have nooooo clue whatsoever about how refrigerators work, so I just copied and pasted from wikipedia.

"Refrigerators work by the use of heat pumps operating in a refrigeration cycle. An industrial refrigerator is simply a refrigerator used in an industrial setting, usually in a restaurant or supermarket. It may consist of either a cooling compartment only (a larger refrigerator) or a freezing compartment only (a freezer) or both. The industry sometimes refers to such units as a "cold box" or a "walk-in." The dual compartment was introduced commercially by General Electric in 1939.

The vapor compression cycle is used in most household refrigerators. In this cycle, a circulating refrigerant such as R134a enters the compressor as a low-pressure vapor at its boiling point. The vapor is compressed and exits the compressor as a superheated high-pressure vapor. The superheated vapor travels through part of the condenser which removes the superheat by cooling the vapor. The vapor travels through the remainder of the condenser and is condensed into a liquid at its boiling point. Before the refrigerant leaves the condenser it will have been subcooled (i.e. below its boiling point). The subcooled liquid refrigerant passes through the metering (or throttling) device where its pressure abruptly decreases. The decrease in pressure results in the flash evaporation and auto-refrigeration of a portion of the liquid (typically, less than half of the liquid flashes). The cold and partially vaporized refrigerant travels through the coil or tubes in the evaporator. There, a fan circulates room air across the coil or tubes, and the refrigerant is totally vaporized, extracting heat from the air which is then returned to the food compartment. The refrigerant vapor, now slightly superheated, returns to the compressor inlet to continue the thermodynamic cycle.

An absorption refrigerator works differently from a compressor refrigerator, using a source of heat, such as combustion of liquefied petroleum gas, or solar thermal energy. These heat sources are much quieter than the compressor motor in a typical refrigerator.

The Peltier effect uses electricity directly to pump heat; refrigerators using this effect are sometimes used for camping, or where noise is not acceptable. They are totally silent, but less energy-efficient than other methods.

Other uses of an absorption refrigerator (or "chiller") would include large systems used in office buildings or complexes such as hospitals and universities. These large systems are used to chill a brine solution that is circulated through the building.

Other alternatives to the vapor-compression cycle but not in current use include thermionic, vortex tube, air cycle, magnetic cooling, Stirling cycle, Malone refrigeration, acoustic cooling, pulse tube and water cycle systems.^[6]"

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sita

@sitakshii

Stunner

+ 4

Posted: 16 years ago

folks as i am a biology student ,so lemme tell u this tht still it is not clearly known tht how many bones a newly born has ,yup !!! the number is surely not 206 (as in adults) but the number of bones in newly born r more than 206 if we are counting the cartilages as bones ,actually cartilages are the immature bones ,on maturity only (in adulthood) cartilages becomes bones .
as far as the working of refrigerator is concerned it works on 4 main principles

1.compression

2.evaporation

3.condensation

4. expansion

i am not good at PHYSICS ,i read this in my class 12th abt the working of refrigerator ,hope i am right.

Edited by sita11 - 16 years ago

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rajnish kumar

@_rajnish_

Inactive

Posted: 16 years ago

folks plz put a question as well while answering
well about baby bone avinash can give ponts
@ godison- you are correct so but copied so 4 points for you
@sita di - you are right it contains 4 cycle but din't explained so 4 points
@avinash- plz give marks

Q- what is the diff between two stroke and 4 stroke engine?

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246851

Hibernated

Posted: 16 years ago

Originally posted by: rajnish_here
Q- what is the diff between two stroke and 4 stroke engine?

first of all, i dont like studies dat much and i am angry😡 for putting this up

answer:

both of them have the same four cycles of suction, compression, (fuel injection)combustion, expansion and exhasution,

bu 2 stroke engine it is complicated in two stroke of piston while in 4 stroke engine its completed in 4 stroke

if an engine makes N revolutions, effective rev for a four stroke engine is N/2 and that for a 2 stroke engine is N, so sp power output for 2 stroke engine is more hence dey r used for light weight portableng say for example an engine of motor cycle

4 strokes engines r supposed to have some advantages somewhere but forgot ICE totally and i wanna curse rajnish for this question

my question @ everyone except rajnish:

i will make it simple, tell how electric heaters work

@rajnish:(its simple for u too)

what is a transformer?

Edited by its me tan - 16 years ago

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Janaki

@RamKiSeeta

Achiever

+ 6

Posted: 16 years ago

#10

Originally posted by: rajnish_here
folks plz put a question as well while answering
well about baby bone avinash can give ponts
@ godison- you are correct so but copied so 4 points for you
@sita di - you are right it contains 4 cycle but din't explained so 4 points
@avinash- plz give marks

Q- what is the diff between two stroke and 4 stroke engine?

A two stroke engine completes intake, compression, combustion, and exhaust in two strokes while the four stroke engine completes it in four strokes.

Q: What is the atomic mass of Palladium?