Q&A - PSLE Science

[Ash001]

Hi Tianzhu/Chrisu,


I did see that qns on pg120 before I post mine I showed that to my husband, he said none of the answer is correct.
Yes indeed it is worrying to see MOE teachers setting question with no correct answer and still insist the school answer is correct. OMG!!!!

About the \"brightness\", it is very subjective to how one define the meaning of brightness. To me, it has to be lightup before it can be measured for brightness. But for others, even if it is not lightup, their consider the 2 bulk is of equal brightness.

Cheers

[Ash001]

I have another question. Also from the Prelim paper


My son chose 2.
School answer is 1.

It seems different people have different intepretation for this qns.
Justification make below is base on understanding that the A/B/C is at that state
Ans 1 : Possible that B is solid @19
Ans 2 : YES for B to be liquid @84. Possible that C to be liquid @84

When I ask some of my friend, some of them chose Ans1, that was because their interpretation was A/B/C turn to that state at that temperature.

When I read the question once again, it did not explicily mention that.


http://i54.tinypic.com/1zcoahz.jpg\">

[tianzhu]

Ash001:

About the \"brightness\", it is very subjective to how one define the meaning of brightness. To me, it has to be lightup before it can be measured for brightness. But for others, even if it is not lightup, their consider the 2 bulk is of equal brightness.

Hi

Could you share with us the explanation from the school teacher?

Did the teacher agree that the two bulbs as connected in diagram C would not be lighted up?

If she did, did the teacher equate “not lighted up” as equivalent to “equal brightness”?

Best wishes.

[tianzhu]

Ash001:

It seems different people have different intepretation for this qns.
Justification make below is base on understanding that the A/B/C is at that state
Ans 1 : Possible that B is solid @19
Ans 2 : YES for B to be liquid @84. Possible that C to be liquid @84

Hi

You’re right to say “Possible that C to be liquid @84”

But it’s also possible that C might be a solid @84.

We may infer that C is a liquid @84,but we cannot infer that B and C are liquid @84.

Please take note of the word and which means both A and B in this particular case.

Based on the context in the question, we may infer that A is a solid @19.

Best wishes

[Nebbermind]

one word.....CHIM!

[atutor2001]

add another word siao

[Tang]

Ash001:

I have another question. Also from the Prelim paper


My son chose 2.
School answer is 1.

It seems different people have different intepretation for this qns.
Justification make below is base on understanding that the A/B/C is at that state
Ans 1 : Possible that B is solid @19
Ans 2 : YES for B to be liquid @84. Possible that C to be liquid @84

When I ask some of my friend, some of them chose Ans1, that was because their interpretation was A/B/C turn to that state at that temperature.

When I read the question once again, it did not explicily mention that.


http://i54.tinypic.com/1zcoahz.jpg\">

Hi,

From the data provided, it is Not Possible To Tell that A is a Solid.
Similarly, it is also Not Possible To Tell that C is a Liquid.

So either (1) or (2) can be accepted as correct.

If I were your son, I would ask the teacher for the 2 marks. Usually, our teachers will either accept both answers as correct or they will void the question and the marks will be adjusted based on total of 98.

[benleetube]

Hi there,


Please help me on the following question.

Which of the following statements is/are false?

A. There is no friction between two smooth surfaces.
B. There are forces acting on a stationary car on a slope.
C. Gravitational force acts only on objects placed above the ground.

The correct answer is A&C. But my answer is A,B and C.

Can anyone explain why? TIA!

[elkniwt]

Hi,


Need help on this qn :

Should the ans be (2) or (3)? Pls advise. Thanks.
http://i56.tinypic.com/oshfki.jpg\">

[Tang]

benleetube:

Hi there,


Please help me on the following question.

Which of the following statements is/are false?

A. There is no friction between two smooth surfaces.
B. There are forces acting on a stationary car on a slope.
C. Gravitational force acts only on objects placed above the ground.

The correct answer is A&C. But my answer is A,B and C.

Can anyone explain why? TIA!

A - False.
There is always friction between two surfaces as long as they are in contact.

B - True
On a slope, the forces acting on the stationary car are gravitational force and frictional force.

C - False
Below ground, gravity is also acting on objects (othewise the objects will float up or pop out of the ground!).