2π × 0.529 Å
4 × 0.529 Å
0.529 × 2π Å
0.529 Å
The correct option is B (2π × 0.529 Å)
First Bohr orbit of 'H' atom has radius r = 0.529 Å
Also, the angular momentum is quantized.
mvr = h/2π
2πr = h/mv
λ = h/mv = 2π × 0.529 Å
The de Broglie's wavelength of electron present in the first Bohr orbit of H atom is 2π × 0.529 Å.
So, the correct option is B