PRACTICE QUESTIONS
Chapter CELL
Q1 What are cell organelles? Give example
Q2 Which cell organelle is known as power house of the cell? Why?
Q3 Name the unit for measuring cell dimensions.
Q4 What is the relationship between micron and millimeter?
Q5 Name the cell organelle which is responsible for all the reactions of cellular respiration in a cell
Q6 Name the cell organelle that is exclusively found in a plant cell.
Q7 Name the five important cell organelle found in a typical cell
Q8 State four differences between plant cell and animal cell
Q9 Name the three plastids and mention one function of each.
Q10 Name the following organelles:
a) Generates energy for the cell organelle
b) Synthesis proteins
c) Control center of the cell
d) Provide skeletal framework of the cell
Q11 State one function of each
a) endoplasmic reticulum
b) Ribosome
c) Golgi bodies
d) Nucleus
e) Plastids
Q12 Draw a neat labeled diagram of plant and animal cell.
Chapter LIGHT
Q1 Define refraction of light.
Q2 Draw the path of ray as it enters from a) rarer to denser
b) Denser to rarer
Q3 What happens to the ray of light as it enter from rarer to denser medium?
Q4 What happens to the light ray as it enter from denser to rarer medium?
Q5 What happens to a light falling normally on the surface separating the two substances?
Q6 State the two rules of refraction
Q7 state the two laws of refraction.
Q8 Define optical density
Q9 Define refractive index
Q10 What happens when sunlight passes through a prism?
Q11 How is rainbow formed? Name the process that is responsible for the phenomenon
Q12 Where should be an object placed in front of a convex lens so as to obtain its real image of the same size? Also draw the ray diagram for the same.
Q13If the image by a lens is diminished, erect and virtual, what is the nature of the lens?
Q14 Name the point on the principal axis of a convex lens to which all rays parallel to the principal axis converges.
Q15 Name two optical instruments that make use of a converging lens
Q16 a) what is a magnifying lens?
b) For what purpose is it used?
c) Why is it also called a simple microscope?
d) Draw a ray diagram to illustrate the magnification in a simple microscope.
Q17 Draw a ray diagram of image formation of the final image in a compound microscope. Also explain its construction and working.
Q18 what are the two common defects of a human eye? How are they corrected?
Q19 Draw a ray diagram of image formation of the final image in an astronomical telescope. Also explain its construction and working.
Q20 Give function of each part of an eye
a) lens
b) ciliary muscle
c) retina
d) iris
e) pupil
f) optic nerve
Q210 complete the table to show image formation by a convex lens
Position of the object Size Nature of the imageAt infinity
Between 2F and infinity
Between F and C
AT 2F
AT F
Saturday, September 26, 2009
Sunday, September 6, 2009
How can insect walk on water?
Insects can walk on water by spreading their weight very carefully as they move. We can see little dents occur in the surface where the ends of their legs touch it. This means that the surface water has been "stretched " but not broken by the weight of the insect.
We can see water act as though it has a skin. If the insect pushes on the water with less force than the attraction of the water molecules , it can walk across the surface . However, ifit is too heavy or clumsy, it will break the surface and sink!. This is known as SURFACE TENSION
Change in the value of 'g'
The value of g decreases with increase in the height above the earth. this means that the weight of a given mass , ie the pull of the earth on a certain mass, decreases as it attains height above the earth's atmosphere. As an object leaves the earth and travels towards the moon it reaches the point where the small pull the earth exert on it exactly equal to the pull by the moon. This point, where the rwo gravitational forces are equal and opposite , is called NEUTRAL or NULL POINT
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