After tracing the path of a ray of light passing through a rectangular glass slab for four different values of the angle of incidence, a student reported his observations in tabular form as given below:

The best observation is

In a locality, hard water, required for an experiment, is not available. However, the following salts are available in the school laboratory:

1. Sodium sulphate 2. Calcium sulphate

3. Magnesium chloride 4. Sodium chloride

5. Calcium chloride 6. Potassium sulphate

Which of the above salts may be dissolved in water to obtain hard water for the experiment?

A student has obtained an image of a well-illuminated distant object on a screen to. Determine the focal length, F1 of the given spherical mirror. The teacher then gave him another mirror of focal length, F2 and asked him to obtain a focused image of the same object on the same screen. The student found that in order to focus the same object using the second mirror, he has to move the mirror away from the screen. From this observation it may be concluded that both the spherical mirrors given to the student were (select the correct option)

Study the following diagrams in which the path of a ray of light passing through a glass prism as traced by four students P, Q, R and S is shown:

When you study a slide showing different stages of budding in yeast, you observe the following stages:

I. The bud may get Separated from the parent body and develop into a new individual.

II. The body of the bud develops and gives rise to another baby bud.

III. A bud comes out in any direction from the body of the parent cell.

IV. Thus they may form a colony. The proper sequence of the above stages is