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Biology; Chemistry; Physics: Post your doubts here!

M.Omar

M.Omar

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FLRNAB said:
There is bending inside the lens as well and you are not taking that into account for the rays not parallel to Principal Axis.
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they R bending inside the lens..all the rays(excluding one passing thru the centre of course)
 
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M.Omar

M.Omar

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princess Anu said:
Whats the main difference between EMF / Voltage/ Potential difference ? o_O
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EMF is of an electrical source.Consider a battery,it will have an e.mf of say 8V
it means tht every coulomb charge it drives round a circuit the Charge(1 C) will carry 8 joules of electrical energy or that it supplies 8J of energy to every Coulomb...Voltage is the unit and frm definition it can be seen V=W/Q where W=energy provided and Q=Charge
Before p.d,U shud know abt electric potential .Electric potential refers to the electrical energy possessed by tht single charge and the potential difference is simply the difference in electric potential when the charge passes frm 2 points.Hence u can see tht why p.d is always between 2 points.because the charge loses electric potential when travelling to the other pt and this gives us the potential difference
It is the lost in enrgy or energy supplied by 1C charge between the pts where the p.d is to be found
 
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FLRNAB

FLRNAB

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M.Omar said:
they R bending inside the lens..all the rays(excluding one passing thru the centre of course)
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But you wouldn't know how much.

Answer this:
http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_s11_qp_12.pdf
Q3. Why isn't the resultant force C?

The car turns in the direction of the resultant force but the centripetal force is towards the center of the circle. There are two forces on the car one from the engine and one due to friction (Centripetal). The resultant is because of the different directions of the these forces. Right? So if we use a graphical method the resultant direction should be in the direction of C?
 
M.Omar

M.Omar

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FLRNAB said:
But you wouldn't know how much.

Answer this:
http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_s11_qp_12.pdf
Q3. Why isn't the resultant force C?

The car turns in the direction of the resultant force but the centripetal force is towards the center of the circle. There are two forces on the car one from the engine and one due to friction (Centripetal). The resultant is because of the different directions of the these forces. Right? So if we use a graphical method the resultant direction should be in the direction of C?
Click to expand...
I don't know if it was only me or not.But I had been given no info abt centripetal force whtsoever except tht it,s perpendicular and all tht.I hooked it up on the internet and must say tht I have grasped tht concept fully.Needless to sya,A more detailed study abt this force shud have been include in our syllabus.
Ok then I,ll tell.
The cntrp force is always towards the centre of circle when CONSTANT motion..The resultant force at tht instant is towards the centre,i.e B and will change in direction retaining dir towards the centre of the circle as the car travles along the circle.At tht instant the resultant force towards B coupled with the speed of the car(which is a must,the car need not exert a force but initially shud have speed) causes it to move in the prejoctory of C but the problem is tht the centripetal force changes in dirction as the car travels a bit forward and thus keeps on changing its dirction ultimately travelling in a circle.One of the most imp part of question is CONSTANT speed which means no other force frm car is applied and resultant wud be B.If u r still wondering tht shudn,t the car be travelling in B direction then remember the initial speed and the fact tht this centrp force is instantaneous and changing continuously so in tht instant the resultan force is B.
visit physicsclassroom site,it,s awesome
Abt ur lens question..Of course we wud know how much it bends coz the pts wud focus at tht pt on the screen originally found by passing thru centre.
Ur,s is correct but not on the context tht the line wud be parallel to P axis ..I mean it,s only parallel when it passes thru FOCAL POINT and then meets the lens.Do u know ehre the focal pt of the lens is?(in tht question)
Like I said ,it,s correct on the pretext tht ray frm top of image despite hitting anywhere on lens will meet the point originally found by the line passing thru centre
 
princess Anu

princess Anu

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DaniyalK said:
The normals are in red and the rays are in green. For Ray 2 the angle of incidence and reflection must match what is given in the question. I've just drawn an estimate.
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How did you figure it out that ray 1 will not be refracted but internally reflected?
 
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