List of top Science Questions asked in CBSE Class IX

How many types of elements together make up the xylem tissue? Name them.
Define the term “tissue”.
An artificial satellite is moving in a circular orbit of radius 42250 km. Calculate its speed if it takes 24 hours to revolve around the earth.
A motorboat starting from rest on a lake accelerates in a straight line at a constant rate of \(3.0\) \(m s^{–2}\) for \(8.0\) \(s\). How far does the boat travel during this time?
Joseph jogs from one end A to the other end B of a straight 300 m road in 2 minutes 30 seconds and then turns around and jogs 100 m back to point C in another 1 minute. What are Joseph’s average speeds and velocities in jogging (a) from A to B and (b) from A to C?
What is osmosis?
Carry out the following osmosis experiment: Take four peeled potato halves and scoos each one out to make potato cups. One of these potato cups should be made from a boiled potato. Put each potato cup in a trough containing water. Now, 
  1. Keep cup A empty 
  2. Put one teaspoon sugar in cup B 
  3. Put one teaspoon salt in cup C 
  4. Put one teaspoon sugar in the boiled potato cup D. Keep these for two hours. Then observe the four potato cups and answer the following: 
  1. Explain why water gathers in the hollowed portion of B and C. 
  2.  Why is potato A necessary for this experiment? 
  3. Explain why water does not gather in the hollowed-out portions of A and D.
How does an Amoeba obtain its food?
Where do the lipids and proteins constituting the cell membrane get synthesized?
Which organelle is known as the powerhouse of the cell? Why?
What would happen to the life of a cell if there was no Golgi apparatus?
What would happen if the plasma membrane ruptures or breaks down?
How is a prokaryotic cell different from a eukaryotic cell?
Make a comparison and write down ways in which plant cells are different from animal cells.
Gravitational force on the surface of the moon is only \(\frac{1}6\) as strong as gravitational force on the earth. What is the weight in newtons of a 10 kg object on the moon and on the earth?
Why will a sheet of paper fall slower than one that is crumpled into a ball?
Amit buys few grams of gold at the poles as per the instruction of one of his friends. He hands over the same when he meets him at the equator. Will the friend agree with the weight of gold bought? If not, why? [Hint: The value of g is greater at the poles than at the equator.]
What do we call the gravitational force between the earth and an object?
What is the acceleration of free fall?
What happens to the force between two objects, if
(i) the mass of one object is doubled?
(ii) the distance between the objects is doubled and tripled?
(iii) the masses of both objects are doubled?
The earth and the moon are attracted to each other by gravitational force. Does the earth attract the moon with a force that is greater or smaller or the same as the force with which the moon attracts the earth? Why?

What is the magnitude of the gravitational force between the earth and a 1 kg object on its surface? (Mass of the earth is 6 × \(10^{24}\) kg and radius of the earth is 6.4 × \(10^6\) m.)

How does the force of gravitation between two objects change when the distance between them is reduced to half?
Complete the following table.
Atomic NumberMass NumberNumber of NeutronsNumber of ProtonsNumber of ElectronsNumber of the Atomic Species

9

-

10

-

-

-

16

32

-

-

-

Sulphur

-

24

-

12

-

-

-

2

-

1

-

-

-

1

0

1

0

-

Which one of the following is a correct electronic configuration of sodium?