# If the radius of first orbit of hydrogen atom is R the de Broglie wavelength of an electron in the third orbit is ?

##### 1 Answer

Jun 9, 2018

#### Explanation:

Radius of

#"r"_"n" = "n"^2"R"#

Where

So, Radius of

#"r" = 3^2"R = 9R"#

From de-Broglie hypothesis and Bohr’s postulate

#"2πr = nλ"#

Wavelength of electron in