Multiple choice what is the circumference of the fourth orbit ? 5λ . 2λ . 4λ . 3λ . Reveal answer Fill a bubble to check yourself C Correct answer Explanation This option is correct because; , λ = h / mv . and from conservation of angular momentum we have = mvr = nh / 2π . => 2πr = nλ . in this case value of n is 4 . hence, this option is correct.