Atoms and Molecules — Science STD 9 — Question

What do you understand by the kinetic energy of a body?

A piece of chalk can be broken into small particles by hammering but a piece of iron cannot be broken into small particles by hammering. Which characteristic of the particles of matter is illustrated by these observations?

Name the device or machines which convert: Heat energy into kinetic energy (or mechanical energy).

Name two ecological problems which are caused by application of synthetic chemicals to crop fields.

What are broilers?

Write down the modes of transmission of tuberculosis.

Classify epithelial tissues on the basis of arrangements of layers.

What is the power of a body which is doing work at the rate of one joule per second?

What are isotopes? Explain by giving an example.

Chemicals used to kill weeds are called _______ .