Electricity — Science STD 10 — Question

Define the following terms.

1. Mineral
2. Ore
3. Gangue

What are strong and weak acids? In the following list of acids, separate strong acids from weak acids. Hydrochloric acid, citric acid, acetic acid, nitric acid, formic acid, sulphuric acid.

A child questioned his teacher that why do organisms resemble their parents more as compared to grandparents. In which way will the teacher explain to the child?

Define reflex action.

Giving reasons, state the ‘signs’ (positive or negative) which can be given to the following:

1. Object distance (u) for a concave mirror or convex mirror.
2. Image distances (v) for a concave mirror.
3. Image distances (v) for a convex mirror.

Write the names given to the vertical columns and horizontal rows in the Modern Periodic Table. How does the metallic character of elements vary on moving down a vertical column ? How does the size of atomic radius vary on moving left to right in a horizontal row? Give reason in support of your answer in the above two cases.

Why could no fixed position be given to hydrogen in Mendeleev’s periodic table?

What is DNA copying? State its importance.

Ozone present in the atmosphere is very important for sustenance of life on earth. Justify.

A narrow beam PQ of white light is passing through a glass prism ABC as shown in the diagram.

Trace it on your answer sheet and show the path of the emergent beam as observed on the screen DE.

1. Write the name and cause of the phenomenon observed.
2. Where else in nature is this phenomenon observed?
3. Based on this observation, state the conclusion which can be drawn about the constituents of white light.