Acids, Bases and Salts — Science STD 10 — Question

An object is placed well outside the principal focus of a convex lens. Draw a ray diagram to show how.

What are the two most common defects of vision (or defects of eye)? How are they corrected?

In the straight wire A, current is flowing in the vertically downwards direction whereas in wire B the current is flowing in the vertically upward direction. What is the direction of magnetic field:

1. In wire A?
2. In wire B?

Name the rule which you have used to get the answer.

Explain how, it would benefit deep sea divers if humans also had gills.

Define phototropism. Give one example of phototropism.

How many 176 Ω resistors (in parallel) are required to carry 5 A on a 220 V line?

What is buck minster fullerene? How is it related to diamond and graphite?

Explain the importance of using in a household electric circuit:

1. Fuse.
2. Earthing wire.

In human beings, where does the gaseous exchange take place?

What happens when a rod of zinc metal is dipped into a solution of copper sulphate? Give chemical equation of the reaction involved.