List of top Science Questions asked in CBSE Class IX

When 3.0g of carbon is burnt in 8.00g oxygen, 11.00g of carbon dioxide is produced. What mass of carbon dioxide will be formed when 3.00g of carbon is burnt in 50.0g of oxygen? Which law of chemical combination will govern your answer?

A driver of a car travelling at \(52\) \(km \;h^{–1}\) applies the brakes Shade the area on the graph that represents the distance travelled by the car during the period. (b) Which part of the graph represents uniform motion of the car?

What is the physical state of water at—
(a) 25°C
(b) 0°C
(c) 100°C ?

Name the following.

Tissue that forms the inner lining of our mouth.
Tissue that connects muscle to bone in humans.
Tissue that transports food in plants.
Tissue that stores fat in our body.
Connective tissue with a fluid matrix.
Tissue present in the brain.

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,

Keep cup A empty
Put one teaspoon sugar in cup B
Put one teaspoon salt in cup C
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:

Explain why water gathers in the hollowed portion of B and C.
Why is potato A necessary for this experiment?
Explain why water does not gather in the hollowed-out portions of A and D.

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?

Fig shows the distance-time graph of three objects A, B and C. Study the graph and answer the following questions:

Which of the three is travelling the fastest?
Are all three ever at the same point on the road?
How far has C travelled when B passes A?
How far has B travelled by the time it passes C?

Complete the following chart:

Name A,B,C,D,E and F in the following diagram showing change in its state

Diagrammatically show the difference between the three types of muscle fibres.

A bullet of mass 10 g traveling horizontally with a velocity of 150 m s^–1 strikes a stationary wooden block and comes to rest in 0.03 s. Calculate the distance of penetration of the bullet into the block. Also, calculate the magnitude of the force exerted by the wooden block on the bullet.

A sound wave travels at a speed of 339 ms^–1. If its wavelength is 1.5 cm, what is the frequency of the wave? Will it be audible?

How do good animal husbandry practices benefit farmers?

In each of the following a force, F is acting on an object of mass, m. The direction of displacement is from west to east shown by the longer arrow. Observe the diagrams carefully and state whether the work done by the force is negative, positive or zero.

Observe work done by the force is negative, positive or zero

A stone of 1 kg is thrown with a velocity of 20 m s^–1 across the frozen surface of a lake and comes to rest after traveling a distance of 50 m. What is the force of friction between the stone and the ice?

The speed-time graph for a car is shown is Fig.

Find how far does the car travel in the first 4 seconds. Shade the area on the graph that represents the distance travelled by the car during the period.
Which part of the graph represents uniform motion of the car?

Find the energy in joules consumed in 10 hours by four devices of power 500 W each.

A hockey ball of mass 200 g traveling at 10 m s^–1 is struck by a hockey stick so as to return it along its original path with a velocity at 5 m s^–1. Calculate the magnitude of the change of momentum that occurred in the motion of the hockey ball by the force applied by the hockey stick.

What is genetic manipulation? How is it useful in agricultural practices?

An object of mass 1 kg travelling in a straight line with a velocity of 10 m s^–1 collides with, and sticks to, a stationary wooden block of mass 5 kg. Then they both move off together in the same straight line. Calculate the total momentum just before the impact and just after the impact. Also, calculate the velocity of the combined object.

Explain the following giving examples.
(a) Saturated solution
(b) Pure substance
(c) Colloid
(d) Suspension

Pragya tested the solubility of three different substances at different temperatures and collected the data as given below (results are given in the following table, as grams of substance dissolved in 100 grams of water to form a saturated solution).

Substance Dissolved	Temperature in K
Substance Dissolved	283	293	313	333	353
	Solubility
Potassium nitrate	21	32	62	106	167
Sodium chloride	36	36	36	37	37
Potassium chloride	35	35	40	46	54
Ammonium chloride	24	37	41	55	66

(a) What mass of potassium nitrate would be needed to produce a saturated solution of potassium nitrate in 50 grams of water at 313 K?
(b) Pragya makes a saturated solution of potassium chloride in water at 353 K and leaves the solution to cool at room temperature. What would she observe as the solution cools? Explain.
(c) Find the solubility of each salt at 293 K. Which salt has the highest solubility at this temperature?
(d) What is the effect of change of temperature on the solubility of a salt?

State which of the following situations are possible and give an example for each of these:

an object with a constant acceleration but with zero velocity
an object moving with an acceleration but with uniform speed.
an object moving in a certain direction with an acceleration in the perpendicular direction.

Write the steps you would use for making tea. Use the words solution, solvent, solute, dissolve, soluble, insoluble, filtrate and residue.

An object of mass 100 kg is accelerated uniformly from a velocity of 5 m s^–1 to 8 m s^–1 in 6 s. Calculate the initial and final momentum of the object. Also, find the magnitude of the force exerted on the object.