Friday, November 16, 2018
02:55 PM (GMT +5)

Go Back   CSS Forums > CSS Compulsory Subjects > General Science & Ability > General Science Notes

Reply Share Thread: Submit Thread to Facebook Facebook     Submit Thread to Twitter Twitter     Submit Thread to Google+ Google+    
 
LinkBack Thread Tools Search this Thread
  #11  
Old Monday, May 28, 2007
Senior Member
 
Join Date: Nov 2006
Location: Qta
Posts: 93
Thanks: 21
Thanked 11 Times in 7 Posts
Kashinov is on a distinguished road
Default

The answer to ur q's are as follows:

1# Why water boils quicker on mountains?

ANS:- This is becoz the atmospheric pressure on mountains is less and as a result the boiling temperature of water or temp. at wch water boils is reduced.....e.g. from 100 degrees centigrade to 97 or 98 degrees centigrade.
So it takes less time o reach this lower temp.


2# Why rainbow is produced in the sky after rainfall and sunlight?

ANS: This is due to the splitting of sunlight into it's 7 basic colours: VIBGYOR.....after sunlight passes thru a raindrop and is a result of refraction.
3# Why water remains cool in Earthenware pitcher?

ANS: This happens becoz when water evaporates from the surface of the pitcher a certain amount of energy or heat is required for evaporation or conversion of water droplets into water vapour so this heat is taken from the surface of the water in the pitcher and the water becomes cool.

4# Why milk is considered as an ideal food?

ANS: Milk contains many of the nutrients and vitamins that are required for the body although the body can not survive on milke alone.

5# Why meat takes longer to cook on the mountains?

ANS: As stated in answer to Q#1.....water boils at a lower temp. and a lower temp is reached by heating the cooking utensil so the meat only gets a lower temp. in wch it has to be cooked.....To solve this problem, the pressure cooker is used.....wch raises the tem of water above becoz of the increase in pressure on the water in the pressure cooker.

6# Why ice and salt mixture is used as a freezing agent in manual ice-cream maker?

ANS: This is becoz salt reduces the temp. of the ice and stops the ice from melting and maintains the temp. and thus keeps the ice-cream cold.

7# Why greenhouse operators paint their glass roof white in summer?

ANS: This is so that the white colour will reflect all the sunlight back and thus prevents the greenhouse from over-heating as white colour has the property of reflecting light and heat.

If u have any more q's just ask me....or ask me @ Questions!!! or at this link: http://www.cssforum.com.pk/central-s...questions.html
__________________
There are only two people in this world whose opinion I care about: One of them is ME and YOU are NOT the other!
Reply With Quote
The Following 2 Users Say Thank You to Kashinov For This Useful Post:
Basit Safi (Friday, December 16, 2016), sumaira85 (Thursday, February 10, 2011)
  #12  
Old Saturday, September 01, 2007
secondopinion02's Avatar
38th CTP (PAAS)
Medal of Appreciation: Awarded to appreciate member's contribution on forum. (Academic and professional achievements do not make you eligible for this medal) - Issue reason: CSP Medal: Awarded to those Members of the forum who are serving CSP Officers - Issue reason: CE 2009 - Merit 531
 
Join Date: May 2007
Location: Karachi
Posts: 218
Thanks: 14
Thanked 149 Times in 64 Posts
secondopinion02 will become famous soon enough
Default Let's Discuss Scientific Reasons

Q. Color Blindness and Haemophilia are more common in men than in women..

ANS: Color blindness and Haemophilia are genetic diseases related to "Sex Chromosomes". For understanding the cause, first one must know the Basic of genetics. The following discussion will also contain some notes regarding basic information and finally the answer for the scientific reasons.


CHROMOSOMES:

In humans there are 46 chromosomes in the nucleas of the Cell. Each chromosomes out of 46 has a pair; therefore, there are 23 pair of chromosomes.

SEX CHROMOSOMES:

Out of 23 pair there is one pair of chromosome that is called "Sex Chromosome" pair. Male have "XY" chromosomes as a pair and females have "XX" chromosomes in a pair. The "Y" chromsome in "XY" Chromosome pair in male dummy and only "X" chromosome is functional in the "XY" pair. While in females, one of the "X" is fully functional just like in male, but the other "X" is partially functional.

AUTOSOMES:

Chromosomes other than sex chromosomes are called "AUTOSOMES". Therefore, there are 22 pair of "AUTOSOMES" and 1 pair of "SEX CHROMOSOMES": 22 Autusomes pair + 1 pair of sex chromosomes = total 23 pair of chromosomes

TRAIT:

Any characteristic in human body that is expressed by a single or a group of genes is called trait; for example, eye color, skin color, hair color, etc

GENES:

Each chromosome has several genes located on it. A single Gene is the unit of trait that our body have, for example, the eye color, blood group, etc. It is not necessary that one gene control a single "trait"; for example, there are different genes that control a single trait as Height, Skin color, etc.

Just as a chromosome has a pair, in the say way, every gene has a pair in the other pairing chromosome.


Recessive trait and Dominant Trait

Take an example of eye color; there are various colors of eyes in human, some have black, some have blue, some have hazel, etc. The most common is black. Now consider the situation on genetic level; if in a pair of chromosome, one chromosome has a black eye color gene and the other has blue; then black will be prevalent and expressed in a human body. Therefore, the blue color is recessive and the black is dominant. Blue color of eyes will express itself when there will be both "blue" trait gene in both of pair of chromosomes.


Now, come to the point of HAEMOPHILIA AND COLOR BLINDNESS:

If there happens to be a gene for "Color blindness" (that is "Recessive" in its nature like my above example for blue eyes color) in X choromosome in male as well as in female. Due to lack of one "X" chromosome in male "XY" sex chromosome, the recessive trait of "Color blindness" will express itself. However, in case of females, there are two "XX" chromsomes and one is partially functional, therefore, if a female have a "Color Blindness" trait on one "X" and absent in the other "X", then the female will not suffer from "Colorblindness "; to be "color-blind" the female needed to have "color-blind" gene on both of the pair of sex chromosomes.

Therefore, due to lack of one "X" chromosome in male it is more prevalent or common in male, while in female both "XX" chromosomes decrease the prevalance of the "Color blindness".


What is a color blind carrier?

ANS: When a female has has one colorblind gene in one chromosomes in a pair of gene while the other chromosome is normal; then the female is said to be "Carrier" however, she is not diseased with "Colorblindness".



Diagramatic Expression:
======================


C = chromosome containing color blind Gene
X = Normal Chromosome

(A) WHEN A COLOR BLIND FEMALE MARRIES WITH A COLOR BLIND MALE
--------------------------------------------------------------



Color Blind Male (CY) Color Blind Female (CX)



. .
. .
. .
. .
. .

CC , CX , CY , XY


CC = Color blind Female

CX = Carrier Female

YC = Color Blind Male

XY = Normal Male


(B) WHEN A COLOR BLIND MAN MARRIES WITH A NORMAL FEMALE
----------------------------------------------------------



Color Blind Male (CY) Normal Female (XX)

. .

. .

. .

. .

CX, CX, XY, XY

CX = Color blind female

CX = Color Blind female

XY= Normal male

XY = Normal male
__________________
Lo! man is in a state of loss. (Al-Asr:103:2) And every small and great thing is recorded. (Al-Qamar:54:53) And guard yourselves against a day in which ye will be brought back to Allah. Then every soul will be paid in full that which it hath earned, and they will not be wronged. (Al-Baqara:2:281)
Reply With Quote
  #13  
Old Tuesday, September 18, 2007
Zirwaan Khan's Avatar
Aryan
Medal of Appreciation: Awarded to appreciate member's contribution on forum. (Academic and professional achievements do not make you eligible for this medal) - Issue reason: CSP Medal: Awarded to those Members of the forum who are serving CSP Officers - Issue reason: CE 2010Moderator: Ribbon awarded to moderators of the forum - Issue reason: Diligent Service Medal: Awarded upon completion of 5 years of dedicated services and contribution to the community. - Issue reason:
 
Join Date: Aug 2007
Location: ISB
Posts: 1,094
Thanks: 363
Thanked 717 Times in 312 Posts
Zirwaan Khan is a glorious beacon of lightZirwaan Khan is a glorious beacon of lightZirwaan Khan is a glorious beacon of lightZirwaan Khan is a glorious beacon of lightZirwaan Khan is a glorious beacon of light
Default Give Scientific Reasons

All the respected senior members are requested to post the scientific reasons for the questions given below . Especially the moderators are requested to do the needful ! I could not found them in my book .

Q.1) Why the front wheels of vehicle lean outwards slightly ?
Q.2) Why do peoples voices sound differently ?
Q.3) why is it easier to push a heavy grass mover than to lift it ?
Q.4) Why is an electric bulb less efficient than a fluorescent tube ?
Q.5)How does the pouring of kerosene oil on stagnant on stagnant water contribute to the eradication of malaria ?
Q.6)Why is it dangerous to have charcoal fire burning in a badly ventilated room ?
Q.7)The works output of a machine is always equal to the work input ?
Q.8)All motions are relative to one another ?
Q.9)Gravity of all the objects is same, regardless of their mass of at a give point on the earth's surface.?
Q.10)Why do you hear thunder after and see flash of light first ?
Q.11)why a bomber does not drop bomb when it is vertically above the target ?
Q.12)Transmission lines carry very high voltages ?
Q.13)A ball dropped vertically on the ground does not rise to its original height ?
Q.14)More stirring is needed when sugar is dissolved in cold cofee than in hot coffee ?
Q.15)Lunar eclipse lasts much longer than solar eclipse ?
Q.16)Goiter is common among people living in hilly areas ?
Q.17)Detergents are better cleaning agent as compared to soaps ?
Q.18) decomposers are imp for life and land and water ?
Q.19)Places near the sea are cooler in summer and warmer in winter than places farther in-land ?
Q.20)A 25 watts incandescent bulb provides much less light than a 25 watts fluorescent tube light ?

These questions aforementioned are from past papers , Every one is requested to please spare some time to figure them out !
take care
__________________
Am in love with the art of madness..
Reply With Quote
  #14  
Old Tuesday, September 18, 2007
Qurratulain's Avatar
Economist In Equilibrium
Medal of Appreciation: Awarded to appreciate member's contribution on forum. (Academic and professional achievements do not make you eligible for this medal) - Issue reason: she won the Essay competitionBest Moderator Award: Awarded for censoring all swearing and keeping posts in order. - Issue reason: Best ModMember of the Year: Awarded to those community members who have made invaluable contributions to the Community in the particular year - Issue reason: For the year 2006
 
Join Date: Feb 2006
Location: The Devil's Paradise
Posts: 1,742
Thanks: 118
Thanked 399 Times in 145 Posts
Qurratulain has a spectacular aura aboutQurratulain has a spectacular aura aboutQurratulain has a spectacular aura about
Default

Quote:
Why do you hear thunder after and see flash of light first ?
I think, light and sound are produced at the same time, but we see the flash first and light later because of light's speed, i.e. faster than the speed of sound



Please rectify me if m' wrong.
__________________
||||||||||||||||||||50% Complete
Reply With Quote
  #15  
Old Tuesday, September 18, 2007
Last Island's Avatar
Royal Queen of Literature
Medal of Appreciation: Awarded to appreciate member's contribution on forum. (Academic and professional achievements do not make you eligible for this medal) - Issue reason: AppreciationBest Moderator Award: Awarded for censoring all swearing and keeping posts in order. - Issue reason: Best ModGold Medal: Awarded to those members with  maximum number of  reputation points. - Issue reason: For the year 2007, 2008, 2009, 2010, 2011Member of the Year: Awarded to those community members who have made invaluable contributions to the Community in the particular year - Issue reason: 2008Diligent Service Medal: Awarded upon completion of 5 years of dedicated services and contribution to the community. - Issue reason: More than 5 years of dedicated servicesModerator: Ribbon awarded to moderators of the forum - Issue reason:
 
Join Date: May 2005
Location: Forest of Fallen Stars
Posts: 7,542
Thanks: 2,408
Thanked 15,766 Times in 4,988 Posts
Last Island is headed toward stardomLast Island is headed toward stardomLast Island is headed toward stardomLast Island is headed toward stardomLast Island is headed toward stardomLast Island is headed toward stardomLast Island is headed toward stardomLast Island is headed toward stardomLast Island is headed toward stardomLast Island is headed toward stardomLast Island is headed toward stardom
Default

Quote:
Lunar eclipse lasts much longer than solar eclipse ?
Lunar eclipse last longer than the solar eclipse because the length of the earth’s umbral shadow cone is more than three times the average distance between the moon and the earth, so the shadow is relatively wide at the point where the moon crosses it.
Quote:
Goiter is common among people living in hilly areas ?
Goiter is common in hilly areas because there is deficiency of Iodine in the water.
Quote:
Detergents are better cleaning agent as compared to soaps ?
A detergent consists of hydrophilic and hydrophobic ends. In case of dirt the detergent pushes the dirt off the surface of the wet surface of the fabric. The washing machine provides the agitation.

Quote:
Decomposers are imp for life and land and water ?
An Ecosystem comprises of produces consumers and decomposers. The decomposers are bacteria and Fungi which degrade organic matter.
Quote:
Places near the sea are cooler in summer and warmer in winter than places farther in-land ?
Sea water keeps the temperature moderate. Because of high specific heat it takes longer for water to get heated up or to get cooled. During summer days the land near the sea gets heated up quickly but the sea water remains cool and thus cool breeze blowing from the sea reduces the heat in the adjoining land area. the land gets cooled quicker but the sea water remains warm and thus the land gets warm breeze from the sea. But the land farther inside does not have this advantage. This accounts for the difference in the climatic conditions.

Quote:
A 25 watts incandescent bulb provides much less light than a 25 watts fluorescent tube light ?
When electric current passes through the fluorescent lamp, the mercury gets very hot and changes to a gas. A short of rays is given off by the gas. The rays when strike against a coating of special material inside the glass tube, it makes the special material glow.

Quote:
More stirring is needed when sugar is dissolved in cold coffee than in hot coffee ?
In hot coffee, the kinetic energy of the molecules is greater because of the high temperature range in it. According to kinetic molecular theory this is not possible in cold coffee. So it is difficult to dissolve sugar in it.
Quote:
A ball dropped vertically on the ground does not rise to its original height ?
All the energy is converted from potential energy to kinetic energy.

Quote:
why is it easier to push a heavy grass mover than to lift it ?
The principle of lever works in pushing a heavy grass mover. With the help of lever we can push the heavy things and even lift them. Moreover the gravity of the earth is 9.8 that attract each object. With this force while lifting the grass mover more force is required then pushing it.

Quote:
why a bomber does not drop bomb when it is vertically above the target ?
Any particle or body which has horizontal motion and at the same time acts like a falling body can be classified as a projectile. It may seem a bit odd that the horizontal motion has no effect on the vertical motion or vice versa, but nevertheless this is true if air resistance is neglected. If a projectile is fired horizontally, it will have a velocity in that direction equal to that given it initially. At the same time it is travelling horizontally, it will fall toward earth, due to gravitational forces exerted on it. While the horizontal motion is at constant velocity the vertical motion is accelerated. This is the reason that a bomber does not drop a bomb when it is vertically above the target.
Quote:
The works output of a machine is always equal to the work input ?
The work done on a machine or the energy provided to the machine is called input. Let effort P acts through a distance d then work done on machine is Pd.

Input = Effort x Distance through which the efforts acts

i.e. Input = P x d

The work done by the machine is called output. If a machine overcomes a force W through distance D, then the useful work done by the machine is W x D. Thus:

Output = Weight x Distance through which the weight acts
i.e. Output = W x D

If we think of an ideal machine which has output equal to the input, the efficiency of an ideal machine is thus one or 100. Thus for an ideal machine:

Output = Input
P x d = W x d
Quote:
Gravity of all the objects is same, regardless of their mass of at a give point on the earth's surface?
If we drop a body from a certain height, it falls to the ground and its velocity continues to increase till it strikes the ground. The body, therefore, gets accelerated as it falls freely, whether light or heavy objects are dropped, they will reach the ground at the same time and the acceleration will reach the ground at the same time and the acceleration will be the same.
__________________
The Me you have always known, the Me that's a stranger still.

Last edited by Aarwaa; Wednesday, August 06, 2008 at 03:32 PM.
Reply With Quote
The Following 4 Users Say Thank You to Last Island For This Useful Post:
Muhammad T S Awan (Wednesday, September 19, 2007), Qurratulain (Tuesday, September 18, 2007), Yellow Minion (Tuesday, February 16, 2016), Zirwaan Khan (Tuesday, September 18, 2007)
  #16  
Old Wednesday, September 19, 2007
Zirwaan Khan's Avatar
Aryan
Medal of Appreciation: Awarded to appreciate member's contribution on forum. (Academic and professional achievements do not make you eligible for this medal) - Issue reason: CSP Medal: Awarded to those Members of the forum who are serving CSP Officers - Issue reason: CE 2010Moderator: Ribbon awarded to moderators of the forum - Issue reason: Diligent Service Medal: Awarded upon completion of 5 years of dedicated services and contribution to the community. - Issue reason:
 
Join Date: Aug 2007
Location: ISB
Posts: 1,094
Thanks: 363
Thanked 717 Times in 312 Posts
Zirwaan Khan is a glorious beacon of lightZirwaan Khan is a glorious beacon of lightZirwaan Khan is a glorious beacon of lightZirwaan Khan is a glorious beacon of lightZirwaan Khan is a glorious beacon of light
Default

@last island

can u please illuminate this a bit more

"All the energy is converted from potential energy to kinetic energy"..
thanks
__________________
Am in love with the art of madness..
Reply With Quote
  #17  
Old Wednesday, September 19, 2007
Last Island's Avatar
Royal Queen of Literature
Medal of Appreciation: Awarded to appreciate member's contribution on forum. (Academic and professional achievements do not make you eligible for this medal) - Issue reason: AppreciationBest Moderator Award: Awarded for censoring all swearing and keeping posts in order. - Issue reason: Best ModGold Medal: Awarded to those members with  maximum number of  reputation points. - Issue reason: For the year 2007, 2008, 2009, 2010, 2011Member of the Year: Awarded to those community members who have made invaluable contributions to the Community in the particular year - Issue reason: 2008Diligent Service Medal: Awarded upon completion of 5 years of dedicated services and contribution to the community. - Issue reason: More than 5 years of dedicated servicesModerator: Ribbon awarded to moderators of the forum - Issue reason:
 
Join Date: May 2005
Location: Forest of Fallen Stars
Posts: 7,542
Thanks: 2,408
Thanked 15,766 Times in 4,988 Posts
Last Island is headed toward stardomLast Island is headed toward stardomLast Island is headed toward stardomLast Island is headed toward stardomLast Island is headed toward stardomLast Island is headed toward stardomLast Island is headed toward stardomLast Island is headed toward stardomLast Island is headed toward stardomLast Island is headed toward stardomLast Island is headed toward stardom
Default

Quote:
can u please illuminate this a bit more
"All the energy is converted from potential energy to kinetic energy"..
Quote:
A ball dropped vertically on the ground does not rise to its original height ?
When the ball is hit on the ground, this work (called potential energy) goes to accelerate the ball (and now is called kinetic energy). When the ball hits the floor this kinetic energy is converted into heat and sound by the impact.
During the bounce, it squashes and comes to a complete stop. As it springs back to its original shape it pushes itself back up off the surface and jumps off the surface like a person doing a standing jump. It can’t bounce back to its original drop height since energy is lost in the ball when it squashes. Most of the energy loss is due to friction inside the ball and it goes into heating the ball. The ball temperature increases slightly every bounce.

Quote:
Why do you hear thunder after and see flash of light first ?
A flash of lightning heats the air around it. Then the air moves outward quickly, making the sound of thunder. We see lightning the instant it lights up the sky. But the sound of thunder moves more slowly through the air. So it always comes after we see the lightning. Sometimes, especially at night, we may see lightning, but not hear the thunder because it is too far away

1. Why the front wheels of vehicle lean outwards slightly ?
2. Why do peoples voices sound differently ?
4. Why is an electric bulb less efficient than a fluorescent tube ?
5. How does the pouring of kerosene oil on stagnant on stagnant water contribute to the eradication of malaria ?
6. Why is it dangerous to have charcoal fire burning in a badly ventilated room ?
8. All motions are relative to one another ?
12. Transmission lines carry very high voltages ?


7 questions are left to be answered. Can anybody answer them?
__________________
The Me you have always known, the Me that's a stranger still.

Last edited by Aarwaa; Wednesday, August 06, 2008 at 03:33 PM. Reason: merge
Reply With Quote
  #18  
Old Wednesday, September 19, 2007
Muhammad T S Awan's Avatar
Senior Member
Medal of Appreciation: Awarded to appreciate member's contribution on forum. (Academic and professional achievements do not make you eligible for this medal) - Issue reason: AppreciationDiligent Service Medal: Awarded upon completion of 5 years of dedicated services and contribution to the community. - Issue reason:
 
Join Date: Mar 2005
Location: Land of Uncia Uncia :)
Posts: 2,071
Thanks: 1,731
Thanked 2,257 Times in 1,099 Posts
Muhammad T S Awan has a brilliant futureMuhammad T S Awan has a brilliant futureMuhammad T S Awan has a brilliant futureMuhammad T S Awan has a brilliant futureMuhammad T S Awan has a brilliant futureMuhammad T S Awan has a brilliant futureMuhammad T S Awan has a brilliant futureMuhammad T S Awan has a brilliant futureMuhammad T S Awan has a brilliant futureMuhammad T S Awan has a brilliant futureMuhammad T S Awan has a brilliant future
Default

To further elaborate:

Quote:
More stirring is needed when sugar is dissolved in cold coffee than in hot coffee ?

In hot coffee, the kinetic energy of the molecules is greater because of the high temperature range in it. According to kinetic molecular theory this is not possible in cold coffee. So it is difficult to dissolve sugar in it.

The saturation capacity of any liquid is low during low level of kinetic energy of its molecules. When we increase the kinetic energy by heating or stirring the solute content holding capacity of liquid molecules is increased likewise its saturation level also increased and it can hold more sugar contents.

Quote:
A ball dropped vertically on the ground does not rise to its original height ?

The ball pushes itself back as per Newton's third law of motion every action has reaction in same amount but in opposite direction. When ball hit on the ground, its kinetic energy is converted into heat and sound. During bounce, it has to pass through the surrounding air and move with the force of gravity. During its way to ground gravitation force help it while during its way back gravitation force hinder its movement. the friction from surrounding air and also consumes its kinetic energy so with the efforts of heat, sound, gravitational force and friction of surrounding air the ball cannot reach upto the level of its drop.

5. How does the pouring of kerosene oil on stagnant on stagnant water contribute to the eradication of malaria ?

malaria is caused by a micro organism 'plasmodium' which lives in Anophelas mosquitoes (perhaps there are two main types of mosquitos perhaps first is cules and anophelas- culex infect birds while anophelas to animals).

mosquito goes through different stages during its development/growth i.e. egg, larvae, pupae and flying mosquito. first three stages are completed in water.

mosquito lay eggs on stagnant water. when keronsene oil is poured in small ponds of stagnant water it covers its upper layer and do not allow air to move inside layers of the water pond. the larvae of mosquito needs air/oxygen to breath, and it come from time to time on water layer to breath, in absence of oxygen mosquito larvae die out. the same process is related with other water animals like fish, if oil is poured into water then animal life inside that water is disturbed badly. other forms of oil can also be utilized but kerosene oil is a bit cheap thats why it is favoured.

i rememberd four five years back that in front plot of my home there was stangnant water, we got petrol from the vehicle and poured on the water and after some time we lit it and with a flash of fire all petrol burnt down and many mosquito larvae-which came near layer of water died out and we witnessed their dead bodies flowing in water...

6. Why is it dangerous to have charcoal fire burning in a badly ventilated room ?

charcoal require oxygen to burn and to produce carbon dioxide, if it is burnt in badly vetilated room tu it can utilize al of its oxygen and producing much carbon dioxide and life can be fatal in such room. further the fume badly detriot the lungs and respiratory passage....
__________________
'Thee woh ik shakhs kay tasawar saay - abb woh ranayee khayal kahaan'
Reply With Quote
The Following 2 Users Say Thank You to Muhammad T S Awan For This Useful Post:
Mahin (Tuesday, September 25, 2007), Yellow Minion (Tuesday, February 16, 2016)
  #19  
Old Wednesday, September 19, 2007
Zirwaan Khan's Avatar
Aryan
Medal of Appreciation: Awarded to appreciate member's contribution on forum. (Academic and professional achievements do not make you eligible for this medal) - Issue reason: CSP Medal: Awarded to those Members of the forum who are serving CSP Officers - Issue reason: CE 2010Moderator: Ribbon awarded to moderators of the forum - Issue reason: Diligent Service Medal: Awarded upon completion of 5 years of dedicated services and contribution to the community. - Issue reason:
 
Join Date: Aug 2007
Location: ISB
Posts: 1,094
Thanks: 363
Thanked 717 Times in 312 Posts
Zirwaan Khan is a glorious beacon of lightZirwaan Khan is a glorious beacon of lightZirwaan Khan is a glorious beacon of lightZirwaan Khan is a glorious beacon of lightZirwaan Khan is a glorious beacon of light
Default

@Tabassum shabbir

Thank you very much for further elucidation . And still 5 questions are left .
Is there any one who can give scientific reasons for the questions left, sir suresh is requested to do the needful soon he interacts with the post .



1. Why the front wheels of vehicle lean outwards slightly ?
2. Why do peoples voices sound differently ?
4. Why is an electric bulb less efficient than a fluorescent tube ?
5. All motions are relative to one another ?
6. Transmission lines carry very high voltages ?
__________________
Am in love with the art of madness..
Reply With Quote
  #20  
Old Friday, September 21, 2007
Junior Member
 
Join Date: Jan 2007
Location: Lahore
Posts: 1
Thanks: 0
Thanked 1 Time in 1 Post
jawwad is on a distinguished road
Default

1. Why the front wheels of vehicle lean outwards slightly ?

Answer: As viewed from the front or rear of the vehicle, camber refers to the "lean" of the wheel from top to bottom. A wheel that leans outward at the top (compared to true vertical) has positive camber. One that leans inward at the top has negative camber. If the wheel is oriented in a true vertical, it's called zero camber.
Camber must always be adjusted to maximize the tread contact patch based on the driving requirements. In most cases, OE specifications will recommend a slightly positive or zero camber to maximize tire wear and traction, and to provide easier steering and greater resistance to directional darting in a straight line.
If the wheel features a static negative camber angle (vehicle sitting idle), this places more tread load at the road surface on the inner shoulder and tread area. Negative camber is regularly employed on performance vehicles (especially race cars on road courses) in order to increase the tire contact patch during hard turns. Since lateral loading (when a car goes into a hard turn) will try to push the top of the inside tire outward, an adequate negative camber angle may compensate for this. So, while the front wheels may display negative camber as the vehicle rolls light, when it goes into a hard turn, ie wheel facing the direction of the turn will try to "straighten up," achieving maximum tread contact with the road. If camber isn't sufficiently negative, this tire would lean too far, causing the inside of the tread to lift and placing excess stress and load only on the outside of the tread and outer shoulder.

Sound is generated in the larynx, and that is where pitch and volume are manipulated. The strength of expiration from the lungs also contributes to loudness, and is necessary for the vocal folds to produce speech.
Fine manipulation of the larynx is used in a great way to generate a source sound with a particular fundamental frequency, or pitch. This source sound is altered as it travels through the vocal tract, configured differently based on the position of the tongue, lips, mouth, and pharynx. The process of altering a source sound as it passes through the filter of the vocal tract creates the many different sounds.
The vocal folds can be held close together (by adducting the arytenoid cartilages), so that they vibrate (see phonation). The muscles attached to the arytenoid cartilages control the degree of opening. Vocal fold length and tension can be controlled by rocking the thyroid cartilage forward and backward on the cricoid cartilage, and by manipulating the tension of the muscles within the vocal folds. This causes the pitch produced during phonation to rise or fall.

It is highly unlikey to find all these voluntary and involuntry movements taking place to produce sound similar in all individuals. That is why, people voices sound differently.

4. Why is an electric bulb less efficient than a fluorescent tube ?

Answer: My dear, in ordinary electric bulb, electic energy is being converted into light energy and heat energy as the tungston filament resists to the flow of electricity and gets hoter and glows.
A fluorescent lamp is a gas-discharge lamp that uses electricity to excite mercury vapor in argon or neon gas, resulting in a plasma that produces short-wave ultraviolet light. This light then causes a phosphor to fluoresce, producing visible light.
The main principle of fluorescent tube operation is based around inelastic scattering of electrons. An incident electron (emitted from the coils of wire forming the cathode electrode) collides with an atom in the gas (such as mercury, argon or krypton) used as the ultraviolet emitter. This causes an electron in the atom to temporarily jump up to a higher energy level to absorb some, or all, of the kinetic energy delivered by the colliding electron. This is why the collision is called 'inelastic' as some of the energy is absorbed. This higher energy state is unstable, and the atom will emit an ultraviolet photon as the atom's electron reverts to a lower, more stable, energy level. The photons that are released from the chosen gas mixtures tend to have a wavelength in the ultraviolet part of the spectrum. This is not visible to the human eye, so must be converted into visible light. This is done by making use of fluorescence. This fluorescent conversion occurs in the phosphor coating on the inner surface of the fluorescent tube, where the ultraviolet photons are absorbed by electrons in the phosphor's atoms, causing a similar energy jump, then drop, with emission of a further photon. The photon that is emitted from this second interaction has a lower energy than the one that caused it. The chemicals that make up the phosphor are specially chosen so that these emitted photons are at wavelengths visible to the human eye. The difference in energy between the absorbed ultra-violet photon and the emitted visible light photon goes to heat up the phosphor coating.
The principle working in fluroescent tube is more efficient and this is the answer to your question.

Question 5. All motions are relative to one another ?

Answer: This belongs to the theory of relativity. Whenever you observe the motion of an object, your observations are relative to your own frame of reference. Let me give you an example. You are traveling in your car and your mobile phone is lying on the dash board. Movement is defined by the change in displacement. The distance between you and your mobile phone is not changing and hence you will observe that the mobile is not moving. Now you pass by a pedestrian walking on the footpath. The distance between him and your mobile phone is changing. So according to him, your mobile phone is moving. So the movement is always relative to the frame of reference. Since your frame of reference and that of the pedestrian were different, so the observations were different.

6. Transmission lines carry very high voltages ?

Voltage is simply the potential difference. At higher potential difference, electricity can be transferred more efficiently. That is why, the potential difference is kept higher when electricity is to be transferred to remote areas.

Last edited by Aarwaa; Wednesday, August 06, 2008 at 03:34 PM.
Reply With Quote
The Following User Says Thank You to jawwad For This Useful Post:
Fatima Saleem (Wednesday, January 21, 2015)
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
More Than 2000 Words to enhance Vocabulary Qurratulain English (Precis & Composition) 23 Sunday, August 19, 2018 08:32 PM
Idioms (A-Z) Argus English (Precis & Composition) 26 Sunday, September 29, 2013 10:58 PM
Philosophy of Science A Rehman Pal Philosophy 0 Sunday, March 18, 2007 04:42 PM
How I See Philosophy Emaan Philosophy 0 Wednesday, July 27, 2005 09:07 PM


CSS Forum on Facebook Follow CSS Forum on Twitter

Disclaimer: All messages made available as part of this discussion group (including any bulletin boards and chat rooms) and any opinions, advice, statements or other information contained in any messages posted or transmitted by any third party are the responsibility of the author of that message and not of CSSForum.com.pk (unless CSSForum.com.pk is specifically identified as the author of the message). The fact that a particular message is posted on or transmitted using this web site does not mean that CSSForum has endorsed that message in any way or verified the accuracy, completeness or usefulness of any message. We encourage visitors to the forum to report any objectionable message in site feedback. This forum is not monitored 24/7.

Sponsors: ArgusVision   vBulletin, Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.