What was important about the Hydrogen bright line emission spectrum?

The emission spectrum lines are the changes in the quantum energy levels of the single electron in the Hydrogen atom.

Explanation:

Electrons move around the hydrogen atom in electron waves patterns. These waves occur in distinct quantum energy levels.

The change from one quantum energy level to another energy level has a definite energy level change. There is a wave length associated with each change in energy levels. These wave lengths have a color associated with them.

Low energy level changes have long wave lengths associated with them giving red and orange colors.

High energy level changes have short wave lengths associated with them giving blue and violet colors.

Note each atom has a unique emission spectrum associated with the energy levels and electron structure of the atom. Helium was first discovered by looking at its emission spectrum as seen in the sun.

Explanation:

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.

in cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. a contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes.

explanation: