Combined Science O lvl Questions.Help =p

jlzk SG

Question 1

Option A right?

Question 2

Er Question 2 i dont really know how to do someone please explain =p thanks!

eagle SG

Question 1, yup

Question 2, A and D are definitely out
do your triangular some of forces thing. If the 3N and 4N thing are at 90 degrees, the resultant would be 5 N. Since the angle is less than 90 degrees, the resultant is less than 5 (use visualisation)

Hence, answer is B (by elimination).

The other method, you can try drawing to scale, of the triangular sum of forces.

jlzk SG

I never since this question before i wonder is this the new syallbus one x.x cause in the old syallbus i didnt get to see before but there might be a probablity it will be tested in the old syallbus and thanks alot eagle =p

jlzk SG

ERRRR i totally don understand what the question wants x.x and it seems to be like electromagnet chapter the induce current one but i dunno how to apply my concepts x.x .Help pls!

Garrick_3658 SG

It's Magnetic Induction Chapter.

Use Fleming's Left Hand Rule and work it out.

Answer is D btw.

jlzk SG

"Fleming's Left Hand Rule" not in my syallabus lei is it new syallubus? x.x

eagle SG

It is in syllabus leh...

At least my combined science student told me it is

jlzk SG

Huh..my one is 5152 leis. Now alot of students taking 5116.Eagle help me check with your students de syllabus see which paper they taking cause i remember my teacher say dont nid learn that one

jlzk SG

More questions nid help x.x psps.. gahhh fore thanks!

Q1.End X of a metal rod attracts the N-pole of a compass needle.What does this show about the rod?

A It could be made of copper but is unmagnetised

B It could be made of copper but with a south pole at X

C It could be made of steel but is unmagnetised

D It could be made of steel but with a North pole at X.

D,confirm out..Is the answer B?

Q2. A permanent magnet moving up and down on the end of a spring balance induces an e.m.f in a coil.Which factor on its own ,will decreate the maximum value of the induced emf.?

A Increase the number of the turns in the coil

B Increasing the strength of the magnet

C Raising the coil

D Raising the support of the spring.

Answer is C right..? cause the answer put D den i was like huh why..

Q3 Which diagram correctly shows the poles induced in both iron bars?

Help x.x i need explantion for this one cause i dun quite understand what it meant..how come the iron bar will got charge one =S

eagle SG

Huh..my one is 5152 leis. Now alot of students taking 5116.Eagle help me check with your students de syllabus see which paper they taking cause i remember my teacher say dont nid learn that one

check from seab website...

maybe tonight I help u check

jlzk SG

Help needed for above question x.x help pls..

secretliker SG

A Increase the number of the turns in the coil

B Increasing the strength of the magnet

C Raising the coil

D Raising the support of the spring.

Answer is C right..? cause the answer put D den i was like huh why..

Raising the coil would make the magnet nearer to the coil, which is likely to increase the emf induced.

Raising the support of the spring makes the spring go further away from the coil, hence reducing the emf induced.

secretliker SG

For the iron bars, the poles are induced on the iron bars due to the permanent magnet at the centre.

Hence a N pole of the magnet would induce a S pole on the side of the iron bar it attacts, and is true the other way round.

Hence Ans: A.

jlzk SG

Thanks pal!

jlzk SG

Q1.End X of a metal rod attracts the N-pole of a compass needle.What does this show about the rod?

A It could be made of copper but is unmagnetised

B It could be made of copper but with a south pole at X

C It could be made of steel but is unmagnetised

D It could be made of steel but with a North pole at X.

D,confirm out..Is the answer B?

What about this?

Garrick_3658 SG

Q1.End X of a metal rod attracts the N-pole of a compass needle.What does this show about the rod?

A It could be made of copper but is unmagnetised

B It could be made of copper but with a south pole at X

C It could be made of steel but is unmagnetised

D It could be made of steel but with a North pole at X.

D,confirm out..Is the answer B?

What about this?

It's C la. Copper is a non-magnetic material leh. Trick question is it.

jlzk SG

o.o =x ops ops sorry didnt really know that =s thanks

Garrick_3658 SG

Q2. A permanent magnet moving up and down on the end of a spring balance induces an e.m.f in a coil.Which factor on its own ,will decreate the maximum value of the induced emf.?

A Increase the number of the turns in the coil

B Increasing the strength of the magnet

C Raising the coil

D Raising the support of the spring.

Answer is C right..? cause the answer put D den i was like huh why..

What is decreate? Opposite of create? Then answer is D, because raising the support of the spring will cause the magnet to move further away from the spring, thus less e.m.f. produced (less magnetic flux linkage cut).

If the Fleming's LHR is not in your syllabus, then you have been doing the wrong papers liao.

eagle SG

http://www.seab.gov.sg/SEAB/oLevel/syllabus/2008_GCE_O_Level_Syllabuses/5152_2008.pdf

I think you are right. Fleming's LHR is not in the syllabus.