Control and Coordination — Science STD 10 — Question

When sunlight is concentrated on a piece of paper by a spherical mirror or lens, then a hole can be burnt in it. For doing this, the paper must be placed at he focus of :

Sustainable development means planned growth with minimum damage to the environment :

To find the focal length of a concave mirror Rahul focuses a distant object with this mirror. The chosen object should be :

A solar cooker may not cook food if.

A convex lens has a focal length of 10cm. At which of the following position should an object be placed so that this convex lens may act as a magnifying glass?

Magnification produced by a rear view mirror fitted in vehicles:

Which of the following metals can be obtained from haematite ore?

During the deficiency of oxygen in tissues of human beings, pyruvic acid is converted into lactic acid in:

A feature of reproduction that is common to Amoeba, Yeast and Bacterium is that :

You are asked to prepare hard water in your laboratory. Select a group from the following groups of salts, any salt of which you may dissolve in distilled water to obtain hard water.