Q&A - PSLE Science

[Niedino]

stary:

Hi all, can someone explain to me about the following?


Catholic High (Prelim 2010) Qns 17 (MCQ)

Diagram 1 below shows what happens when the first side of Disc X faces Disc Y and Diagram 2 shows the second side of Disc X facing the same side of Disc Y.

http://farm6.static.flickr.com/5072/5838972960_7ec136b5a3_b.jpg


Based on the above diagrams, what could we conclude about Discs X, Y and Z?

A Disc X is a magnet.
B Disc Y is a magnet.
C Disc Y is magnetic.
D Disc Z is non-magnetic.

(1) A and B only
(2) C and D only
(3) A, B and D only
(4) B, C and D only

Ans: 3 (My ans: 1)

Fact is that we cannot assume that Z is non-magnetic... It might be magnetic.The unlike poles of Disc Y and Z might be facing each other...

Thx in advance... :imdrowning: :imdrowning:

Hi Stary,

In this case, I'll agree with you that the answer should be 1, as there was no indication that Z was magnetic or not. However, if the question had reversed Disc Y rather than X, then the answer might be 3, as there was no repulsion. But having said that, Z could be a magnetic material, so you cannot have a firm conclusion on that. I suppose the true answer is (1), but the seller of the question paper might have put a wrong answer down.

Hope it helps!

[stary]

Niedino:

stary:

Hi all, can someone explain to me about the following?


Catholic High (Prelim 2010) Qns 17 (MCQ)

Diagram 1 below shows what happens when the first side of Disc X faces Disc Y and Diagram 2 shows the second side of Disc X facing the same side of Disc Y.

http://farm6.static.flickr.com/5072/5838972960_7ec136b5a3_b.jpg


Based on the above diagrams, what could we conclude about Discs X, Y and Z?

A Disc X is a magnet.
B Disc Y is a magnet.
C Disc Y is magnetic.
D Disc Z is non-magnetic.

(1) A and B only
(2) C and D only
(3) A, B and D only
(4) B, C and D only

Ans: 3 (My ans: 1)

Fact is that we cannot assume that Z is non-magnetic... It might be magnetic.The unlike poles of Disc Y and Z might be facing each other...

Thx in advance... :imdrowning: :imdrowning:

Hi Stary,

In this case, I'll agree with you that the answer should be 1, as there was no indication that Z was magnetic or not. However, if the question had reversed Disc Y rather than X, then the answer might be 3, as there was no repulsion. But having said that, Z could be a magnetic material, so you cannot have a firm conclusion on that. I suppose the true answer is (1), but the seller of the question paper might have put a wrong answer down.

Hope it helps!

Hi Niedino,

Thx for yr explanation!
I hope we're rite...

[Bing_He]

Just want to share a simple thought.

I believe all parents has think beyond the required thought process of a Pri 6 student.
In answering the OE questions, we need to bear in mind that the teachers are looking at the correct level of knowledge that a Pri 6 possess.
Take for example air composition, will question being ask more than the simple make up of air, or the photosysthesis cycle replenish oxygen, instead asking the effect of carbon dioxide level affecting the environment.
Just my two cents worth.
Cheers mate.

[Kloggy]

Hi, can someone help with the following:


An experiment was carried out by placing duckweeds in two beakers with 500ml of water each. 10 ml of bleach was added to one of the beakers. Write an hypothesis for the experiment.

The answer provided was that the duckweed will grow better in the water with bleach added. But why ?

Thanks.

[hashroop]

Hi, pls help. For a developing human foetus, which system(in correct order) develops first.

Circulatory, muscular, skeletal,digestive, respiratory?

Thanks

[Nebbermind]

Are the above 2 PSLE qns? Did revision with my boy last yr and have not come across such qns.


Or r these taken from some GEP science qn ppr?

[hashroop]

Nebbermind:

Are the above 2 PSLE qns? Did revision with my boy last yr and have not come across such qns.


Or r these taken from some GEP science qn ppr?

At least mine is. My DS2 sat for Mavis Prelim exams yesterday and one of the question was on the developement of human foetus.

[Kloggy]

Nebbermind:

Are the above 2 PSLE qns? Did revision with my boy last yr and have not come across such qns.


Or r these taken from some GEP science qn ppr?

Yes, duckweed question from River Valley, 2010, Prelims.

[P5G]

Please help.


16. The table below shows the number oif organisms in a habitat.

Organism | Number of organisms
--------------------------------------
Ixora |2
Mynahs | 3
Slugs | 7
Butterflies | 11
Snails | 9
Caterpillars | 7

How many populations of animals are there altogether?

(1) 39
(2) 37
(3) 5
(4) 4

Given answer: (4)

Should the correct answer be (3)?

TIA.

[starlight1968sg]

Kloggy:

Hi, can someone help with the following:


An experiment was carried out by placing duckweeds in two beakers with 500ml of water each. 10 ml of bleach was added to one of the beakers. Write an hypothesis for the experiment.

The answer provided was that the duckweed will grow better in the water with bleach added. But why ?

Thanks.

What? add bleach and duckweed will grow better ??? :yikes: