IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Subject Doubts => IGCSE/ GCSE => Sciences => Topic started by: moon on November 11, 2009, 04:20:23 pm

Title: Physics ppr1 doubts
Post by: moon on November 11, 2009, 04:20:23 pm
Plz i need help in NOV. 2006 Q 16, didn't understand how the answer is calculated here....   ??? ???
Title: Re: Physics ppr1 doubts
Post by: Ghost Of Highbury on November 11, 2009, 04:26:44 pm
22cm - 100'C

2cm - 0'C

that means 22-2 cm - 100'C

20cm - 100'C

1cm - 5'C

now,

the reading in the thermometer is 8cm

which is 6cm above from 2

1cm - 5'C
6cm - 30'C

Answer : C, 30'C

hope u understood
Title: Re: Physics ppr1 doubts
Post by: moon on November 11, 2009, 04:40:14 pm
ok, I understood that question now $ thanx a lot 4 helping me....
Title: Re: Physics ppr1 doubts
Post by: Ghost Of Highbury on November 11, 2009, 04:48:11 pm
welcome
Title: Re: Physics ppr1 doubts
Post by: nits94 on November 12, 2009, 10:23:59 am
hey I have a problem... please help me with this.. Thanks :)
 
Title: Re: Physics ppr1 doubts
Post by: @d!_†oX!© on November 12, 2009, 11:24:31 am
 :P :P
no idea nits...sorry....if any1 knows plss help her and give a reason too..... :)
Title: Re: Physics ppr1 doubts
Post by: @d!_†oX!© on November 12, 2009, 11:57:12 am
hey guys...
does any1 over here know that why is the anode in a CRO cool??
Title: Re: Physics ppr1 doubts
Post by: Ghost Of Highbury on November 12, 2009, 11:57:24 am
guess it shud be A

 any how the current is (direction) the magnetic field is still dere na, so it attracts the soft iron
Title: Re: Physics ppr1 doubts
Post by: Ghost Of Highbury on November 12, 2009, 11:59:43 am
Quote from: @d!_†oX!© on November 12, 2009, 11:57:12 am
hey guys...
does any1 over here know that why is the anode in a CRO cool??

anode is really cool man!

he wears cool shades all the time, a cigar stuck between his lips looks so cool!!

also, he loves chocolate milkshake , with ice cubes!.. isnt that cool!! whoa!
Title: Re: Physics ppr1 doubts
Post by: @d!_†oX!© on November 12, 2009, 12:07:08 pm
aadi!!!!!
dude m serious....lol..for the first time:P
pata hai ya nahi bhai??
Title: Re: Physics ppr1 doubts
Post by: Saladin on November 12, 2009, 12:11:19 pm
Wait until u meet cathode...

he wears CAT boots and gear.

He got everyone jumpin up and down whenever, they see him, from copper ions to any other positive ion!!

he got this amazing lamboghini baybe... and he knows how to treat it good..

he is the master of all odes.

hahahhehe ;D :D
Title: Re: Physics ppr1 doubts
Post by: astarmathsandphysics on November 12, 2009, 12:12:26 pm
It is A. Iron is easily magnetized so is always attracted to a magnetic field
Title: Re: Physics ppr1 doubts
Post by: @d!_†oX!© on November 12, 2009, 12:13:09 pm
yeah i get it...so u guys in a really cool mood today huh??!!
Title: Re: Physics ppr1 doubts
Post by: astarmathsandphysics on November 12, 2009, 12:13:53 pm
The anode should be warm. Electrons are emitted from the anode, aided by the anode being heated.
Title: Re: Physics ppr1 doubts
Post by: @d!_†oX!© on November 12, 2009, 12:15:07 pm
sir but i remember electrons being emitted from the cathode....
and i check the answer...it says that the anode is cool ???
Title: Re: Physics ppr1 doubts
Post by: astarmathsandphysics on November 12, 2009, 12:18:03 pm
wait I will check.
Title: Re: Physics ppr1 doubts
Post by: astarmathsandphysics on November 12, 2009, 12:20:21 pm
yes right. The cathode is heated so electrons are emitted aided by being heated. I will check on the anode being cooled.
Title: Re: Physics ppr1 doubts
Post by: astarmathsandphysics on November 12, 2009, 12:23:30 pm
The anode is cooled so it DOES NOT emit electrons by thermionic emmision
Title: Re: Physics ppr1 doubts
Post by: nits94 on November 12, 2009, 03:40:33 pm
Quote from: A@di on November 12, 2009, 11:57:24 am
guess it shud be A

 any how the current is (direction) the magnetic field is still dere na, so it attracts the soft iron
It is A. Iron is easily magnetized so is always attracted to a magnetic field
ya the ans is A...Thanks :) :)
Title: Re: Physics ppr1 doubts
Post by: Ghost Of Highbury on November 12, 2009, 03:41:06 pm
welcome
Title: Re: Physics ppr1 doubts
Post by: @d!_†oX!© on November 12, 2009, 03:45:11 pm
hey guys this one please:

s08/qp1/ques38


it says that the beta particles are electrons(which i right) and it is emitted from the nucleus
can u explain the latter(bolded)
Title: Re: Physics ppr1 doubts
Post by: Ghost Of Highbury on November 12, 2009, 04:05:37 pm
Quote from: @d!_†oX!© on November 12, 2009, 03:45:11 pm
hey guys this one please:

s08/qp1/ques38


it says that the beta particles are electrons(which i right) and it is emitted from the nucleus
can u explain the latter(bolded)

definitely from the nucleus, because beta particles are fromed when neutron splits. neutron in nucleus. simple..
Title: Re: Physics ppr1 doubts
Post by: Trinion on November 12, 2009, 07:01:34 pm
When beta decay occurs, a neutron turns into a proton, antineutrino and an electron. The electron does NOT come from the orbit in this case.
Title: Re: Physics ppr1 doubts
Post by: astarmathsandphysics on November 12, 2009, 10:43:43 pm
The equation is neutron>proton+electron+antineutrino and the reaction happens in the nucleus
Title: Re: Physics ppr1 doubts
Post by: @d!_†oX!© on November 13, 2009, 05:42:02 am
thanks aadi, trinion and astar!!