Atoms and Molecules — Science STD 9 — Question

Which of the following symbols of elements are incorrect? Give their correct symbols.
Sodium So

If action is always equal to the reaction, explain how a horse can pull a cart.

What happens to an animal cell when it is placed in a very dilute external medium? Why?

Name the device which is used to produce sound in laboratory experiments.

Micronutrients are required by plants in smaller quantities. From the list given below, select only micronutrients required by plants. N, P, K, Ca, Mg, S, Zn, Cu, Mb and Cl

A body goes round the sun with constant speed in a circular orbit. Is the motion uniform or accelerated?

The features that best describe the cells of parenchyma cells are:

1. Dead cells, thick walled, no inter cellular.
2. Living cells, thin-walled, no intercellular spaces.
3. Dead cells, thin-walled, large intercellular spaces.
4. Living cells, thin-walled, large intercellular spaces.

What is upthrust?

What name is given to those elements which are neither good conductors of electricity like copper nor insulators like sulphur?

State whether speed is a scalar or a vector quantity. Give reason for your choice.