Question

1. Which metal vapours are used in bright street lights? 2. Which gas is used in display coloured light advertisements 3. Name the metal used to coat digits of watches so as to see time in the dark Name the metal present in chlorophyll. Which element is present in vitamin Bj2? Which compound of lead is present in yellow paints? Name the non-metal used in skin ointments. Sun and stars are made up of plasma. Explain. Why is the sky blue in colour?

Answer 1

1. Generally Sodium vapour and mercury vapour are used in street lights.
2[ depends on colour]
.Neon -orange, Hydrogen for Red, Helium-yellow, Carbon dioxide-white and mercury-blue
3.radium
4. Cobalt
5.Magnesium
6.Lead Chromate
7.Sulphur
8. Plasma is the state which consists of ions and electrons. Sun and stars has large amount of Hydrogen and helium gas. Due to high temperature these gaseous atoms gets completely ionized hydogen ions and helium ions. The sun and stars consists of plasma.
9. Due to scattering of blue light, sky appears blue in colour.

Answer 2

Explanation:

A common or traditional definition of matter is "anything that has mass and volume (occupies space)". For example, a car would be said to be made of matter, as it has mass and volume (occupies space). The observation that matter occupies space goes back to antiquity.