Author Topic: IGCSE PHYSICS DOUBTS HERE !!!!  (Read 54687 times)

elemis

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Re: IGCSE PHYSICS DOUBTS HERE !!!!
« Reply #210 on: May 12, 2011, 03:47:20 pm »
Calculation of the least count is not a necessity to determining the zero error.

When the jaws are closed you can simply read of the scales and determine the zero error.

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Re: IGCSE PHYSICS DOUBTS HERE !!!!
« Reply #211 on: May 12, 2011, 03:58:35 pm »
okay, there are certain methods to go about on the calculations for both the instruments.

you have to understand first WHY do you actually use those instruments rather than a regular ruler. The simple and primary reason being they provide more accuracy. There are others as well - they can calculate the diameter accurately etc.

vernier callipers (vc) and micrometer gauge (mg) are NOT the same thing however the theoretical calculation is similar.

VC has a least count of 0.01 cm so it can calculate the diameter of an object to 3 sfg.
MG has an LC of 0.001 cm
^ These are standard least counts for instruments. This can vary too.

Google the rest please because theres a lot to learn and i cannot possibly type everything because i have to go study chemistry.

http://www.tutorvista.co.uk/content/physics/physics-i/measurement-and-experimentation/vernier-callipers-animation.php

http://www.tutorvista.co.uk/content/physics/physics-i/measurement-and-experimentation/screw-gauge.php

^ These should cover pretty much everything up including the calculation for LC and zero error.
oh so so sorry... i knew that thr use.. but i didn't get the calculation part :(
from where is .10, 4 and .01 coming :(

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Re: IGCSE PHYSICS DOUBTS HERE !!!!
« Reply #212 on: May 12, 2011, 10:55:09 pm »
Are you sure you understand what a zero error is ?
i got confuded from these question by book simply says read where the scales coincide then if it + add it to ur reading now still confused by what the previous question asked
~~~Yarab everything turns alright at the end ~~~
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elemis

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Re: IGCSE PHYSICS DOUBTS HERE !!!!
« Reply #213 on: May 13, 2011, 08:31:13 am »
i got confuded from these question by book simply says read where the scales coincide then if it + add it to ur reading now still confused by what the previous question asked

Normally, when you close the jaws of a vernier calliper or those of a micrometer the scale MUST show a reading of zero.

That's because its obviously measuring nothing.

However, sometimes due to callibration errors or misuse of the equipment when you close the jaws the scale DOESN'T read zero.

Instead the scale will show some value. This value, when the jaws are closed, is the zero-error of your vernier calliper/micrometer.

If you use a vernier calliper with a zero error you must do the following :

measured length as per vernier  MINUS zero error.

Offline curiousguy

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Re: IGCSE PHYSICS DOUBTS HERE !!!!
« Reply #214 on: May 13, 2011, 07:38:46 pm »
can some one please answers these question of paper 1 2003,2004,2005 queation 39. And please explain me with detail how to find half life and its concept.

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Re: IGCSE PHYSICS DOUBTS HERE !!!!
« Reply #215 on: May 13, 2011, 07:43:53 pm »
can some one please answers these question of paper 1 2003,2004,2005 queation 39. And please explain me with detail how to find half life and its concept.
2003, 2004 and 2005 question 39th which one summer or winter? :-\

And about the half life, its just the half of the real life( i.e. life/2 for one half life)
Its when the material decays, Gamma decays slowest, then comes the beta and finally alpha :)
Decays meant that it's radioactivity is reduced :)
« Last Edit: May 13, 2011, 07:47:55 pm by $~SauD~$ »

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elemis

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Re: IGCSE PHYSICS DOUBTS HERE !!!!
« Reply #217 on: May 14, 2011, 03:53:45 am »
http://www.xtremepapers.me/CIE/index.php?dir=Cambridge%20IGCSE/0625%20-%20Physics/&file=0625_w02_qp_1.pdf

question 10 please.
Thanks in advance.


It is accelerating hence its velocity is increasing. Thus, its KE will increase (KE = 0.5mv2)

Since it is moving upwards it is attaining a new vertical height, hence, its GPE increases.

Answer = D

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Re: IGCSE PHYSICS DOUBTS HERE !!!!
« Reply #218 on: May 14, 2011, 11:06:44 am »

elemis

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Re: IGCSE PHYSICS DOUBTS HERE !!!!
« Reply #219 on: May 14, 2011, 11:30:50 am »

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Re: IGCSE PHYSICS DOUBTS HERE !!!!
« Reply #220 on: May 14, 2011, 11:58:05 am »

elemis

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Re: IGCSE PHYSICS DOUBTS HERE !!!!
« Reply #221 on: May 14, 2011, 12:24:11 pm »
oh oh, sorry
Thats not the link, this one:
http://www.xtremepapers.me/CIE/Cambridge%20IGCSE/0625%20-%20Physics/0625_w10_qp_12.pdf

The reciprocal of the gradient of the graph is the spring constant since :

F=ke   ;   k = F/e

K in this case is equal to 2.5

If the spring length when the unknown weight is added is 16.4 :

F =ke

F = 2.5*(16.4-15)

F = 3.5 N

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Re: IGCSE PHYSICS DOUBTS HERE !!!!
« Reply #222 on: May 14, 2011, 12:46:44 pm »
The reciprocal of the gradient of the graph is the spring constant since :

F=ke   ;   k = F/e

K in this case is equal to 2.5

If the spring length when the unknown weight is added is 16.4 :

F =ke

F = 2.5*(16.4-15)

F = 3.5 N
Shukran(arabic).. Thank you... xie xie(chinese)...

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Re: IGCSE PHYSICS DOUBTS HERE !!!!
« Reply #223 on: May 14, 2011, 01:03:26 pm »
It is accelerating hence its velocity is increasing. Thus, its KE will increase (KE = 0.5mv2)

Since it is moving upwards it is attaining a new vertical height, hence, its GPE increases.

Answer = D
Thanks :)
rep

**RoRo**

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Re: IGCSE PHYSICS DOUBTS HERE !!!!
« Reply #224 on: May 14, 2011, 02:09:22 pm »
Can someone please explain to me how do you solve Q38 in this paper?
http://www.xtremepapers.me/CIE/Cambridge%20IGCSE/0625%20-%20Physics/0625_w10_qp_11.pdf