Select the correct answer. which types of orbitals are found in the principal energy level n = 3? a. s, d b. s, p, d c. s, p d. s, p, f e. s, d, f

B. s, p, d

Explanation:

Principle Quantum Numbers: This quantum number describes the size of the orbital. It is represented by n. n = 1,2,3,4

Azimuthal Quantum Number: This quantum number describes the shape of the orbital. It is represented as 'l'. This quantum number is used to describe shape. The value of l ranges from 0 to (n-1). For l = 0,1,2,3... the orbitals are s, p, d, f...

Thus if the value of  n =3 , the possible values of l are 0 to (3-1) , i.e. 0, 1 and 2.

where l= 0 represents s subshell, l= 1 represents p subshell and l= 2 represents d subshell.

Thus the correct option is B.

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.