Physics, Chemistry and Biology: Post your doubts here!

[Ahmed Alaa El-shamy]

Oh thanks >.>
Ignore my post .. I see how it is.

Oh sorry man i swear i did not see ur reply , my mistake !!! ur post is helpful though so thank u and sorry again
PEACE

 

[chaotic]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Physics (0625)/0625_w10_qp_31.pdf

Anyone can please explain how to answer the first and last questions? please.

 

[sma786]

Moment= forceX perpendicular distance of the line of action of force to the pivot

thanks =]

 

[Abby ay]

Hey
anyone knows the formula of the moment of force??

moment of a force= force x perpendicular distance from the force to the pivot

 

[Abby ay]

Can someone explain the left-hand and right-hand rules?

http://www.passmyexams.co.uk/GCSE/physics/electric-motors.html#2
refer this.

 

[chaotic]

http://www.passmyexams.co.uk/GCSE/physics/electric-motors.html#2
refer this.

AWESOME! Thanks alot

 

[natsume hyuga]

to increase the sensitivity of a thermometer you have to increase the length of the capillary tube and and to increase the range u have to have a finer capillary tube and a larger bulb right? Anything for linearity? no right?

 

[Abby ay]

AWESOME! Thanks alot

anytime

 

[ThatReallyReallyWeirdDude]

whatever u feel like

Actually it says on the front of the exam, 3 significant figures and 2 decimal places for angles.

 

[ThatReallyReallyWeirdDude]

to increase the sensitivity of a thermometer you have to increase the length of the capillary tube and and to increase the range u have to have a finer capillary tube and a larger bulb right? Anything for linearity? no right?

Sensitivity:
To increase, decrease diameter of capillary tube or use a liquid with higher expansivity.
Range:
Opposite to sensitivity
Increase diameter of capillary tube or use liquid with lower expansivity
Linearity:
If a thermometer isn't linear then all you can do is replace the liquid with a linear liquid

 

[chaotic]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Physics (0625)/0625_w10_qp_31.pdf

Anyone can please explain how to answer the first and last questions? please.

Can someone solve this question? with explanation, very urgent.

 

[IGCSE O/L student]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Physics (0625)/0625_w10_qp_31.pdf

Anyone can please explain how to answer the first and last questions? please.

question 1: draw a perpendicular lyn, n measure 60 degrees frm da lyn 2 da left. measure 30 degrees frm da lyn 2 da ryt. xtend da lyns. since u hv 2 use da scale given, use a compass 2 measure 5cm, n cut an arc on da ryt lyn frm da point @ which da 2 lyns meet. measure 8.7cm, n cut an arc on da left lyn. frm da left arc, measure 5cm n draw a large arc. frm da ryt arc measure 8.7cm n draw anothr large arc. da 2 arcs shud intersect. join da point of intersection 2 da previous 2 arcs. dis shud form a parallelogram. connect da point @ which da first 2 lyns meet 2 da point @ which da 2 arcs intersect. measure da lyn, n usin da scale, calculate it into newtons. dats da value of da resultant.

Q 11) wen a dc voltage, dere will b a horizontal lyn @ da top of da screen. wen an ac voltage is used, dere will b waves formed. draw @ least 3. wen an ac voltage is used, n if a diode is connected, dere will b half of da waves draw in da previous screen. ie; only da top portions OR only da botttom portions of da waves will b visible.

 

[xxxt]

accelerationg anode only accelerates the electrons ... it has high dc voltage connected across it ! focuscing anode makes the electrons in a beam ! usally they both r intergrated n made into one

thanx!!

 

[za Shadow]

HELP!!!!!!!!! PLZZZZZZZ
q 6 b)
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Physics (0625)/0625_s07_ms_3.pdf
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Physics (0625)/0625_s07_qp_3.pdf

 

[IsraJ]

HELP!!!!!!!!! PLZZZZZZZ
q 6 b)
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Physics (0625)/0625_s07_ms_3.pdf
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Physics (0625)/0625_s07_qp_3.pdf

6 b)(i) it says it's almost parallel to AE, so the angle of incidence is 90 degrees
6 b)(ii) at critical angle the refracted ray is at 90 degrees while here the incident ray is 90 degrees. So that refracted ray in this case is the critical angle which is 43 degrees.
6 b)(iii) refractive index= sin i/sin r so sin 90/sin 43 = 1.47

 

[sma786]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Physics (0625)/0625_w07_qp_3.pdf question (6) (a)
can someone like draw the rays n show them to me or something?

 

[ThatReallyReallyWeirdDude]

HELP!!!!!!!!! PLZZZZZZZ
q 6 b)
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Physics (0625)/0625_s07_ms_3.pdf
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Physics (0625)/0625_s07_qp_3.pdf

it says the ray is ALMOST parallel to AE - that means it has an angle of incidence of ALMOST 90.
Mark scheme says anything between 88-90 is acceptable, so I'd write 89.
The critical angle occurs when the ray going from more optically dense medium to less optically dense medium is refracted with an angle of refraction of 90*. b)i) Is that but opposite - you're looking at the refracted ray of angle 90* as an incident ray of angle 90* - so the critical angle is 43*
refractive index = 1/sinC where C is the critical angle
so n=1/sin43 = 1.466

 

[natsume hyuga]

Sensitivity:
To increase, decrease diameter of capillary tube or use a liquid with higher expansivity.
Range:
Opposite to sensitivity
Increase diameter of capillary tube or use liquid with lower expansivity
Linearity:
If a thermometer isn't linear then all you can do is replace the liquid with a linear liquid

thanks alot

 

[za Shadow]

6 b)(i) it says it's almost parallel to AE, so the angle of incidence is 90 degrees
6 b)(ii) at critical angle the refracted ray is at 90 degrees while here the incident ray is 90 degrees. So that refracted ray in this case is the critical angle which is 43 degrees.
6 b)(iii) refractive index= sin i/sin r so sin 90/sin 43 = 1.47

THANK U SOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO MUCH

it says the ray is ALMOST parallel to AE - that means it has an angle of incidence of ALMOST 90.
Mark scheme says anything between 88-90 is acceptable, so I'd write 89.
The critical angle occurs when the ray going from more optically dense medium to less optically dense medium is refracted with an angle of refraction of 90*. b)i) Is that but opposite - you're looking at the refracted ray of angle 90* as an incident ray of angle 90* - so the critical angle is 43*
refractive index = 1/sinC where C is the critical angle
so n=1/sin43 = 1.466

THANK U SOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO MUCH

 

[Ahmed Raouf]

Can someone explain the left-hand and right-hand rules?

left hand rule is used to determine the direction of force if given direction of current and magnetic field. On your left hand raise your thumb(will represent force) ,make your first finger face with the direction of magnetic field, your second middle finger should be perpendicular to the first finger and facing the direction of current, the ndirection where your thumb looks is the direction of force. i found a video on youtube showing you what i just said hope it helps,