Q&A - PSLE Science

[atutor2001]

P5G:

Please help.


http://i51.tinypic.com/w7jx1l.gif\">


TIA.

My interpretation of the graph is that Line 1 is for Transpiration and Line 2 is Photosynthesis.

(a) The rat will die and the plant will continue to survive.

(b) The rat died because it has no food. The plant can survive because it can continue to make its own food.

Personally, I think it is ok to say that both rat and plant will survive because rat can survive for 1 week without food. However, I have chosen to answer that rat will die because my guess is that the question is testing on \"difference in ability to make its own food between plant and animal\"

[atutor2001]

P5G:

Please help.


http://i53.tinypic.com/nben88.gif\">

TIA.

(a) The rate of photosynthesis of water plants without the presence of light (in darkness) is faster at higher temperature.
OR
The rate of photosynthesis of water plants without the presence of light (in darkness) is slower at higher temperature.
....

(b) All the water plants will die because there is no light for it to carry out photosynthesis to make food.

[atutor2001]

P5G:

Please help.


http://i54.tinypic.com/20tldzk.gif\">

TIA.

(i) Ostrich should be placed in Group C

(ii) The organisms are grouped by the type of food they eat. Group A are carnivores, B are Herbivores and C are Omnivores

[Herbie]

i hv a qn.


Raju wante to find whether a nail was magnetised. He put it near a magnet, a compass and a paper clip. He recorded his observations below

A. It repelled the magnet.
B. It attracted the magnet.
C. It attracted the paper clip.
D. It could move the compass needle.

From which of the above observations can be sure that the nail waagnetised?

1. A only
2. A and C only
3. B and C only
4. A, B, C and D

[atutor2001]

Herbie:

i hv a qn.


Raju wante to find whether a nail was magnetised. He put it near a magnet, a compass and a paper clip. He recorded his observations below

A. It repelled the magnet.
B. It attracted the magnet.
C. It attracted the paper clip.
D. It could move the compass needle.

From which of the above observations can be sure that the nail waagnetised?

1. A only
2. A and C only
3. B and C only
4. A, B, C and D

Answer is (1) A only because magnet can only be confirmed by repulsion. Attraction can happen between a magnet and a magnetic material.

[Herbie]

hi atutor,

The answer on the answer sheet is 3.

If the nail is being magetised, it shld also be able to attract the paper clip and attract the magnet too right??

[atutor2001]

Herbie:

hi atutor,

The answer on the answer sheet is 3.

If the nail is being magetised, it shld also be able to attract the paper clip and attract the magnet too right??

I have to disagree with the answer given in the answer sheet.

The key word in the question is \"can be sure\". That means the option chosen must be 100% correct with no allowance for other possibility.

It is true that if the nail is being magnetised, it should be able to attract the paper clip and the magnet.

However,

Possibility 1
It is also true that if the nail is NOT magnetised, it would still be attracted to the magnet.

Possibility 2
It is also true that if the nail is NOT magnetised but if the paper clip is magnetised, the nail will be attracted to the paper clip. (unless it is stated clearly in the question that the paper clip is not magnetised)

Therefore, it is a norm that to confirm whether if an object is a magnet, we need to use repulsion.

[Vanilla Cake]

P5G:

By the way, do you know the answers to Chong Fu 2011 CA2 Science.

Should the answer for 39 be
a). A and D instead of A and F.
c). Kinetic energy --> Kinetic energy + ??? (No idea) instead of Kinetic energy --> Heat energy + Sound energy.
Please help. TIA.

Hi P5G,

39(a)
No kinetic energy when the roller coaster was at the starting point and when it hits the bumper (finishing point). So, the positions are A and F.

When it is at the starting point, it has no kinetic energy but it has the most gravitional potential energy. So, the position should be A.

39(c)
When it hits the bumper at F, it will produce sound and heat due to the impact. So the energy conversion will be from kinetic energy to sound energy and heat energy.

Hope this helps.

[P5G]

Vanilla Cake:

P5G:

By the way, do you know the answers to Chong Fu 2011 CA2 Science.

Should the answer for 39 be
a). A and D instead of A and F.
c). Kinetic energy --> Kinetic energy + ??? (No idea) instead of Kinetic energy --> Heat energy + Sound energy.
Please help. TIA.

Hi P5G,

39(a)
No kinetic energy when the roller coaster was at the starting point and when it hits the bumper (finishing point). So, the positions are A and F.

When it is at the starting point, it has no kinetic energy but it has the most gravitional potential energy. So, the position should be A.

39(c)
When it hits the bumper at F, it will produce sound and heat due to the impact. So the energy conversion will be from kinetic energy to sound energy and heat energy.

Hope this helps.

Hi,

Noted. Thanks. I will just have to ignore those wordings below the boxes as they are so confusing.

[P5G]

Please help.


http://i53.tinypic.com/2na3535.gif\">


Should the answer for (c) be:

Plot D. It has the least number of plants per plot so there is less competition for nutrients, water and space.


TIA.