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Physics: Post your doubts here!

MissBellum

MissBellum

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Can someone explain how to solve Oscillation questions and some Alternating current questions that use radians. Im not sure how to work it on my calculator, i always get confused on these questions :confused: My working is always 100% correct but the answer is never right :oops: Could someone show me a few examples so i dont make this mistake in my exam tomorrow :sick:
 
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waleed302

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MiniSacBall said:
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s10_ms_23.pdf

Q1 a ii)
How to do it i mean apart from adding 0.02, why do we add 0.01, is it because of the +-1 digit.
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Yes, after you add 0.02, you have to take into consideration the other information they give you which is +-1 digit. Since it's asking for the maximum, you'd obviously use +1 digit. I know it's kind of confusing but I see no other explanation for this!
 
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boxfire1995

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sagar65265 said:
I'm not able to understand your question; hopefully this guess might help, if not i'm sorry, could you explain again?

Uranium-235, according to the given equation, can decay into Barium-141 and Krypton-92; each nucleus in the sample used will undergo this reaction, and since the equation is balanced for conservation of charge and mass, each nucleus of Uranium, when hit by a neutron, will produce 1 nucleus of Barium, another of Krypton and 3 neutrons, along with some energy.

So, when 1.2 grams of Uranium-235 decay, we need to find out how many nuclei of Barium-141 are produced. Since we have a one-one relation (i.e. one nucleus of
U-235 produces one nucleus of Ba-141) we can say that the number of Barium nuclei produced is equal to the number of Uranium nuclei that take part in the nuclear reaction. In this case, all of them react, so the number of atoms (and correspondingly, the number of nuclei) of U-235 is given by

Avogadro's Number * No. of moles

The number of moles of nuclei in the Uranium sample is given by

(Mass of Sample)/(Mass of 1 mole of element)

Substituting the values, we get

6.02 * 10^23 * 1.2/235 = 3.07 * 10^21 nuclei.

Hope this helped!

Good Luck for all your exams!
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Thank you! I was over looking the molar ratio part. JazakAllah! May Allah help you like you helped me. :)
 
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