1) The energy of an electron having de-Broglie wavelength λ is (where, h= planck's constant, m= mass of electron) A) h2mλ B) h22mλ2 C) h22m2λ2 D) h22m2λ Answer: Option BExplanation:We know that , λ=h√2m(KE) on taking square on both sides,we get λ2=h22m(KE) KE=h22mλ2