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Physics: Post your doubts here!
- Thread starter XPFMember
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can some one pls explain this ques? Question 5b (ii) why does the current have to be 40mA? I don't understand. 
http://www.xtremepapers.com/papers/...and AS Level/Physics (9702)/9702_s03_qp_2.pdf
http://www.xtremepapers.com/papers/...el/Physics (9702)/9702_s03_ms_1+2+3+4+5+6.pdf
http://www.xtremepapers.com/papers/...and AS Level/Physics (9702)/9702_s03_qp_2.pdf
http://www.xtremepapers.com/papers/...el/Physics (9702)/9702_s03_ms_1+2+3+4+5+6.pdf
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M would be zero when there's a destructive interference so the phase difference of the 2 waves at P = 180
and the formula of path difference would be of destructive interference
and the formula of path difference would be of destructive interference
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sahania, cud u help me wth this???
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Alpha Particles
Certain radionuclides of high atomic mass (Ra226, U238, Pu239) decay by the emission of alpha particles. These alpha particles are tightly bound units of two neutrons and two protons each (He4 nucleus) and have a positive charge. Emission of an alpha particle from the nucleus results in a decrease of two units of atomic number (Z) and four units of mass number (A). Alpha particles are emitted with discrete energies characteristic of the particular transformation from which they originate. All alpha particles from a particular radionuclide transformation will have identical energies.
Beta Particles
A nucleus with an unstable ratio of neutrons to protons may decay through the emission of a high speed electron called a beta particle. This results in a net change of one unit of atomic number (Z). Beta particles have a negative charge and the beta particles emitted by a specific radionuclide will range in energy from near zero up to a maximum value, which is characteristic of the particular transformation.
Gamma-rays
A nucleus which is in an excited state may emit one or more photons (packets of electromagnetic radiation) of discrete energies. The emission of gamma rays does not alter the number of protons or neutrons in the nucleus but instead has the effect of moving the nucleus from a higher to a lower energy state (unstable to stable). Gamma ray emission frequently follows beta decay, alpha decay, and other nuclear decay processes.
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The ability of radioactivity to pass through materials is called its penetrating ability.It depends on the size of the radioactive particle.a-particles are the biggest,b-particles are very much smaller and g-rays have no mass.The bigger the particle,the more likely it is to collide with the atoms of the material.The collision will stop the particle going through the material.a-particles are the biggest and are least able to penetrate a material.Paper will stop them and even in air a-particles only travel for a few centimetres before they are stopped.b-particles are stopped by a few millimetres of aluminium.g-rays are able to penetrate the most and will even find their way through metres of concrete.
Certain radionuclides of high atomic mass (Ra226, U238, Pu239) decay by the emission of alpha particles. These alpha particles are tightly bound units of two neutrons and two protons each (He4 nucleus) and have a positive charge. Emission of an alpha particle from the nucleus results in a decrease of two units of atomic number (Z) and four units of mass number (A). Alpha particles are emitted with discrete energies characteristic of the particular transformation from which they originate. All alpha particles from a particular radionuclide transformation will have identical energies.
Beta Particles
A nucleus with an unstable ratio of neutrons to protons may decay through the emission of a high speed electron called a beta particle. This results in a net change of one unit of atomic number (Z). Beta particles have a negative charge and the beta particles emitted by a specific radionuclide will range in energy from near zero up to a maximum value, which is characteristic of the particular transformation.
Gamma-rays
A nucleus which is in an excited state may emit one or more photons (packets of electromagnetic radiation) of discrete energies. The emission of gamma rays does not alter the number of protons or neutrons in the nucleus but instead has the effect of moving the nucleus from a higher to a lower energy state (unstable to stable). Gamma ray emission frequently follows beta decay, alpha decay, and other nuclear decay processes.
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The ability of radioactivity to pass through materials is called its penetrating ability.It depends on the size of the radioactive particle.a-particles are the biggest,b-particles are very much smaller and g-rays have no mass.The bigger the particle,the more likely it is to collide with the atoms of the material.The collision will stop the particle going through the material.a-particles are the biggest and are least able to penetrate a material.Paper will stop them and even in air a-particles only travel for a few centimetres before they are stopped.b-particles are stopped by a few millimetres of aluminium.g-rays are able to penetrate the most and will even find their way through metres of concrete.
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take out the wavelengths of both the frequencies by the formula v=fλ
then use the formula of destructive path difference to determine the number of minima for both the wavelengths you have calculated. I hope i'm clear
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Whats d formula for destructive path interfernce???take out the wavelengths of both the frequencies by the formula v=fλ
then use the formula of destructive path difference to determine the number of minima for both the wavelengths you have calculated. I hope i'm clear
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(n+1/2) π
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what is n?
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yep the table well i dunt understand how to gt the answer do we use the formula P=V^2/R throut or js add the 1.5kw depding on the switch being closed confusd
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the further the distance D the more the wave will spread out, the less the intensity which means a lower amplitude too because intensity is proportional to A^2..did u get it?can anyone please explain how brightness is linked with the formula a = lambda x D/x
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yep the table well i dunt understand how to gt the answer do we use the formula P=V^2/R throut or js add the 1.5kw depding on the switch being closed confusd
ok it's pretty simple .. dont worry ...
the first row .. power is zero because S1 is open ..
the second one ... S3 is open .. so we dont count resistor C, S2 is closed so we dont count resistor B .. we only need A's poer which is 1.5kW .. which they told us is the power for each resistor ..
the third one .. we only count A and C .. using 1/R + 1/R .. calculate the resistance to be 1/38.4 + 1/38.4 .. the resistance is 19.2 ohms .. THEN USING P=V^2/R = THE ANSER IS 3
the fourth one .. A and B are counted so . resistance ins eries is R1+R2 = 76.8 ohms .. using the same formula u get .. 0.75kW
the fifth one .. is all three resistore .. 1/76.8 + 1/38.4 .. and the same way u get 2.25kW
the further the distance D the more the wave will spread out, the less the intensity which means a lower amplitude too because intensity is proportional to A^2..did u get it?
thanx a ton brotha!
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hey calm down .. theres no point of rebelling against CIE the night before this exam.. get through it .. cancel your grade later if you dont need it bro ..
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Physics in Cie is really messed up and stupid , the questions are hard themselves and on top of that , they give us 1 hour to do the paper ! , 1 hour !!!! are you insane????? , we cant even think cause of this messed time limit , plus there is nothing in the text book , Physics is insane , i soo regret taking CIE physics , worst decision of my life , no matter how hard to study for it , u cant do good , Cambridge doesn't reward you for ur handwork .
Who agrees with me ???
Who agrees with me ???
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But its soo hard , iv studied so hard , and now i dont feel any confidence , i feel stupid looking at this paper...