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Old Jun 16th 2009, 09:56 AM   #1
s3a
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Colour addition/substraction problem (I think)

Q:
Sandra wore a red and white shirt to a party, at which all the lights were covered with blue filters.

In this light, what colour did her shirt appear to be?

A:
Black and blue

How can you tell?!

Any help would be greatly appreciated!
Thanks in advance!
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Old Jun 16th 2009, 07:04 PM   #2
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Originally Posted by s3a View Post
Q:
Sandra wore a red and white shirt to a party, at which all the lights were covered with blue filters.

In this light, what colour did her shirt appear to be?

A:
Black and blue

How can you tell?!

Any help would be greatly appreciated!
Thanks in advance!
White light is due to addition of primary colors i.e red, blue and green. Blue filter absorbs red and green transmitting blue color.
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Old Jun 16th 2009, 08:33 PM   #3
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hix

I don't understand very well.
Oh,is there anyone here can help me with this question?
200g of water at 90oC is poured into a cup (mass:210g)at 10oC.The temperature of the water and the cup settles to 75oC.
Assuming that no heat escaped into the environment during the process described,what is the specific heat of the cup?From 1-4 below choose the best answer,where the specific heat of water is 4.2 J/g.K?
1)0.22 J/g.K
2)0.71
3)0.92
4)1.2
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Old Jun 16th 2009, 08:55 PM   #4
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Originally Posted by aki2510 View Post
I don't understand very well.
Oh,is there anyone here can help me with this question?
200g of water at 90oC is poured into a cup (mass:210g)at 10oC.The temperature of the water and the cup settles to 75oC.
Assuming that no heat escaped into the environment during the process described,what is the specific heat of the cup?From 1-4 below choose the best answer,where the specific heat of water is 4.2 J/g.K?
1)0.22 J/g.K
2)0.71
3)0.92
4)1.2
You have not elaborated what exactly you did not understand.
Regarding the problem, find the heat lost by the hot water. Equate it to heat gained by the cup and the cold water.
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Old Jun 17th 2009, 05:27 AM   #5
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Hix,you didn't explain elaborately.Can you give me the exact key?=>
In fact,I'm very bad at physics because when I studied at high school,I almost neglected this subject.=D
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Old Jun 17th 2009, 09:33 AM   #6
s3a
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Lol did people forget about me?
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Old Jun 17th 2009, 09:58 AM   #7
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Originally Posted by s3a View Post
Lol did people forget about me?
When you see this reply on TV, sprinkle a drop of water on the TV screen.
Identify the colors. So the white light isthe mixtur of the three primary colors, red, green and blue.When light passes through blue filter, red and green light are absorbed, But blue is transmitted. So the dress appears blue.
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