Answer:
Explanation:
94.91 nm = 1237.5 / 94.91 eV
= 13.038 eV
Energy of ground state = - 13.6 eV
Energy of higher state to which it jumped
= - 13.6 + 13.038
= - .562 eV
If n be the orbit to which it jumped
13.6 / n² = .562
n = 5 ( approx )
b )
1281 nm = 1237.5 / 1281
= .966 eV
Energy of second photon = 13.038 - .966
= 12.072 eV
Wavelength of second photon
= 1237.5 / 12.072
= 12.51 nm
b ) Energy of intermediate level
= - 0.562 - .966 eV
= - 1.528 eV
If it be n th level
13.6 / n² = 1.528
n = 3
Answer:
A potentiometric pH meter is used to measure the pH of a solution.
Explanation:
A pH meter is an common instrument that is used to measure the hydrogen-ion concentration in aqueous solutions , the meter indicates its acidity or alkalinity and is expressed as pH.
The pH meter measures the difference in electrical potential between a pH electrode and a reference electrode, hence the pH meter is often called a potentiometric pH meter. The difference in electrical potential is related to the pH of the solution.
Potentiometric pH meters consists of a simple electronic amplifier and a pair of electrodes, alternatively it may consist of a combination electrode, and some form of display calibrated in pH units. It usually has a glass electrode and a reference electrode, or a combination electrode. The electrodes, or probes, are inserted into the solution to be tested and pH values are read off.
Answer:
the last one is the correct anwser