Question

what potential difference must be applied to an electron microscope to produce an electron beam of wavelength 0.41 Α°. Please answer by using class 12 physics formula...

Answer 1

energy of electron beam of wavelength 0.41A° = workdone due to potential difference

or, hc/λ = eV

here , h is Plank's constant i.e., h = 6.63 × 10^-34 J.s

c is speed of light in vaccum i.e., c = 3 × 10^8 m/s

λ is wavelength of electron beam i.e., λ = 0.41 A° = 0.41 × 10^-10 m

e is charge on electron i.e., e = 1.6 × 10^-19 C

so, 6.63 × 10^-34 × 3 × 10^8/0.41 × 10^-10 = 1.6 × 10^-19 × V

or, V = (6.63 × 3)/(0.41 × 1.6 ) × 10^(-34 + 8 + 10 + 19)

= (6.63 × 3)/(0.41 × 1.6) × 10³

= 30.32 × 10³ V

= 30.32 kV

hence, 30.32kV, potential difference must be applied to the electron microscope.