Life Processes — Science STD 10 — Question

What is the difference between the molecules of soaps and detergents, chemically? Explain the cleansing action of soaps.

How are power and focal length of a lens related? You are provided with two lenses of focal length 20cm and 40cm respectively. Which lens will you use to obtain more convergent light?

Distinguish between good conductors, resistors and insulators. Name two good conductors, two resistors and two insulators.

When zinc metal is treated with a dilute solution of a strong acid, a gas is evolved, which is utilised in the hydrogenation of oil. Name the gas evolved. Write the chemical equation of the reaction involved and also write a test to detect the gas formed.

Compare the nervous system and endocrine system (hormonal system) for control and coordination in humans.

What are the two ways in which cow-dung can be used as a fuel? Which of them is better and why?

Why is blood circulation in human heart called double circulation?

How do metals reacts with dilute acids? Explain with the help of an example.

Give a few characteristics of asexual reproduction.

Give the exact location and function of the cerebellum.