Question

If kinetic energy of an electron is increased 4 times the wavelength of the de broglie

Answer 1

if
kinetic energy increases wavelength decreases
because the kinetic energy is inversely proportional to the wavelength if kinetic energy increases four times the wavelength decreases four times

Answer 2

Answer:1/2 times

Explanation:

de broglie wavelength

(lamda)L= h/(2mKE)1/2 ........1

h is planks constant, m is mass of electron & KE is kinetic energy...

from eq 1

L(lamda) is inversly proportional to (KE)1/2

L/L1 = {(KE)f /(KE)i}1/2

(KE)f = 4(KE)i (given)

so L/L1 = 2 or

L1 = L/2

it means de broglie wavelength of electron is decreased to half times the initial value....