Biology; Chemistry; Physics: Post your doubts here!

[luckywang]

Where do v use them!!!

use in transmitting electricity... use step-up transformer to increase voltage then only use cable to transmit the electricity to different area because current will cause joule heating.... at different area, different step-down transformer is used to decrease the voltage to require amount.... any error?

 

[luckywang]

Can some1 give me example of D.C and A.C current and also tell me wher do v use dem

D.C use in radio.... a.c is the power supply...

 

[luckywang]

May be it will help u

Ways toincrease e.m.f in an A.C Generator:​

1. Decrease distance between the magnet and coil.
2. Use stronger Magnet
3. Increase the speed of moving the magnets
4. Increase no. of turns on the coil.

​

Question: Describe theprocess/operation of the A.C Generator ​

1. Turn the wire.
2. The wire cuts through the magnetic field as it turns.
3. This produces an induced emf.
4. Because of the load, an induced current is produced.

erm... i wan circular motion? anyway.. thanks... its useful

 

[luckywang]

http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Physics (5054)/5054_w09_qp_1.pdf

Explain mcq 8 ... how the center of mass was determined ?

answer is C... cross the bus with two line from each corner, then the two lines will intersect at C... since the question stated just about to topple over, so draw a downward line from C and the line will be just inside the base of the bus...
correct me if my explaination incorrect...

 

[A star]

http://www.xtremepapers.com/papers/...onal O Level/Physics (5054)/5054_s03_qp_1.pdf can some body please explain Q 20. i knw wht is answer but y?

 

[luckywang]

http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Physics (5054)/5054_s03_qp_1.pdf can some body please explain Q 20. i knw wht is answer but y?

answer is B?

 

[NIM]

use in transmitting electricity... use step-up transformer to increase voltage then only use cable to transmit the electricity to different area because current will cause joule heating.... at different area, different step-down transformer is used to decrease the voltage to require amount.... any error?

thnx... quite helpful

 

[NIM]

erm... i wan circular motion? anyway.. thanks... its useful

i dont hav any fr circular motion so i thought maybe this will help u...

 

[NIM]

D.C use in radio.... a.c is the power supply...

ok got it!!!
thnx...

 

[Acer]

Hey guys....need help in these questions fast: ashiqbal SalmanPakRocks

1. w11 qp_21 Question 3 (a) (i)

2. s11 qp_22 Question 5 (a)

3. s10 qp_22 Question 11 (a)

4. w10 qp_22 Question 9 (a)

5. w09 qp_2 Question 11 (c) (i)

THanks in advance...please please reply as soon as possible

 

[ashiqbal]

explain Q9(v): why are the forces added?
http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Physics (5054)/5054_w11_qp_21.pdf

please can anyone give a reasonable explanation?

 

[amna shah]

http://www.xtremepapers.com/papers/CIE/Cambridge%20International%20O%20Level/Physics%20(5054)/5054_w09_qp_1.pdf

mcq 22, 26, 32, 34 please explain ... thankx

 

[NIM]

Describe the operation of Transformer...

 

[NIM]

http://www.xtremepapers.com/papers/...onal O Level/Physics (5054)/5054_w09_qp_1.pdf

mcq 22, 26, 32, 34 please explain ... thankx

for 26 answer is 'A'
use formula 1/R=1/R+1/R+1/R
1/R= 1/4 +1/2 +1
1/R=7/4
CROSS MULTIPLY
R= 4/7 or 0.57
for the rest of the questions em so bad to explain...

 

[luckywang]

please can anyone give a reasonable explanation?

my explaination rejected?

 

[NIM]

my explaination rejected?

which one...

 

[luckywang]

http://www.xtremepapers.com/papers/...onal O Level/Physics (5054)/5054_w09_qp_1.pdf

mcq 22, 26, 32, 34 please explain ... thankx

i give answer first...
22=A?
26=A?
32=C?
34=D?
correct?

 

[luckywang]

which one...

because it wan upward force? mean the answer is resultant + Weight? if just resultant the rocket is unable to move? too heavy?

 

[Rimsa]

why can birds stand on overhead transmission lines without suffering any harm?
-their bodies are of high resistance?
-good insulator feet
-no potential difference b/w feet
- spaces b/w feathers act as insulators..
which one? shouldnt the reason be that they arent connected to earth so thats why? :s

 

[luckywang]

why can birds stand on overhead transmission lines without suffering any harm?
-their bodies are of high resistance?
-good insulator feet
-no potential difference b/w feet
- spaces b/w feathers act as insulators..
which one? shouldnt the reason be that they arent connected to earth so thats why? :s

because the cable is insulated? if not our house would no electricity when raining?