Question

a) Consider a LED bulb with 940 lumens illumination of cold light (6500 K). Calculate the emission wavelength and how many photons it releases per second.

b) What is the kinetic energy of an electron after being accelerated by a voltage source of 10 kV? What is the DeBroglie wavelength of this electron?

c) The wavelength of an electron accelerated by a potential of 1000 eV is:

to. 0.39 pm

b. 1.24 pm

c. 39 pm

to. 1240 pm

d) The moment of a photon with a wavelength of 500 nm is:

to. 3.97x10-19 Kgms-1

to. 1.32x10-27 Kgms-1

to. 3.31x10-31 Kgms-1

to. 1.32x10-36 Kgms-1