de-Broglie wave length of Bohr's first orbit is lambda.What is the circumference of third orbit?

The de-Broglie's wavelength in 1^(st) Bohr's orbit is

An electron is moving in Bohr's fourth orbit. Its de Broglie wavelength is lambda . What is the circumference of the fourth orbit?

If the de Broglie wave length of the fourth Bohr's orbit of hydrogen atom is 4 Å, the circumference of the orbit is:

The de Broglie wave present in fifth Bohr orbit is:

Find the de Broglie wavelength of revolving electron for the Bohr's first orbit of circumference 2pir .

The de-Broglie wavelength of an electron in the first Bohr orbit is