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ALL PHYSICS DOUBTS - POST HERE !!

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Ghost Of Highbury:

--- Quote from: Shazizzzle on May 26, 2010, 10:28:45 am ---OH! Okay! Thanks! :)
I Can't believe we weren't told this!
+rep :)

--- End quote ---
Anytime.

Dana:
A 2 kg mass of copper is heated for 40 s by a heater that produces 100 J / s.
The specific heat capacity of copper is 400 J / (kg K).
What is the rise in temperature?
A 5K
B 10K
C 20K
D 50K

Help?  :(

Ivo:

--- Quote from: Ivo on May 26, 2010, 10:25:54 am ---
145         0           145
      A  ->   beta +       Z
92          -1            93

Answer is D, oui ou non?

--- End quote ---

So is this now right?

237         0           237
      A  ->   beta +       Z
92          -1            93

So is it B then because 237-93 is 144, which is no of neutrons.  And protons is 93?  Can we think of it this way?

Vin:

--- Quote from: Ivo on May 26, 2010, 10:25:54 am ---
145         0           145
      A  ->   beta +       Z
92          -1            93

Answer is D, oui ou non?

--- End quote ---

Je suis desole, ce n'est pas la reponse ! Even i thought the same way ! But turned out to be B

Ivo:

--- Quote from: Dana on May 26, 2010, 10:31:43 am ---A 2 kg mass of copper is heated for 40 s by a heater that produces 100 J / s.
The specific heat capacity of copper is 400 J / (kg K).
What is the rise in temperature?
A 5K
B 10K
C 20K
D 50K

Help?  :(

--- End quote ---

P=E/T so E=PT=100*40=4,000

E=mCT so T=E/mc = 4000/(2*400) = 5

A?

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