English Medium इयत्ता ९ - CBSE Question Bank Solutions for Science

A solution is always a liquid. Comment.

Can a solution be heterogeneous?

A group of students took an old shoebox and covered it with black paper from all sides. They fixed a source of light (a torch) at one end of the box by making a hole in it and making another hole on the other side to view the light. They placed a milk sample contained in a beaker/tumbler in the box as shown in Fig.2.4. They were amazed to see that milk taken in the tumbler was illuminated. They tried the same activity by taking a salt solution but found that light simply passed through it?

(a) Explain why the milk sample was illuminated. Name the phenomenon involved.

(b) The same results were not observed with a salt solution. Explain.

(c) Can you suggest two more solutions that would show the same effect as shown by the milk solution?

During an experiment, the students were asked to prepare a 10% (Mass/Mass) solution of sugar in water. Ramesh dissolved 10g of sugar in 100g of water while Sarika prepared it by dissolving 10g of sugar in water to make 100g of the solution.

(a) Are the two solutions of the same concentration

(b) Compare the mass % of the two solutions.

Arun has prepared a 0.01% (by mass) solution of sodium chloride in water. Which of the following correctly represents the composition of the solutions?

A motorcyclist drives from A to B with a uniform speed of 30 km h^–1 and returns back with a speed of 20 km h^–1. Find its average speed.

There are three solids made up of aluminium, steel and wood, of the same shape and same volume. Which of them would have the highest inertia?

Velocity versus time graph of a ball of mass 50 g rolling on a concrete floor is shown in Fig. 9.1. Calculate the acceleration and frictional force of the floor on the ball.

Which one of the following has a long term effect on the health of an individual?

List out some useful traits in the improved crop?

Comment upon the following:-

rigidity

Comment upon the following:-

compressibility

Comment upon the following:-

fluidity

Comment upon the following:-

filling a gas container

Comment upon the following:- 

shape

Comment upon the following:-

kinetic energy

Comment upon the following:-

density

To make a saturated solution, 36 g of sodium chloride is dissolved in 100 g of water at 293 K. Find its concentration at this temperature.

Explain the term Saturated solution giving examples.

Why is it not possible to see an atom with naked eyes?