An electron has the same de Broglie wavelength as the wavelength ...

[wrbasek0]

An electron has the same de Broglie wavelength as the wavelength of a 1.8 eV photon.
 
  What is the speed of the electron? (melectron = 9.11  10-31 kg, c = 3.00  108 m/s, 1 eV = 1.60  10-19 J)
  A) 840 m/s B) 910 m/s C) 980 m/s D) 770 m/s E) 1100 m/s

Question 2

A sphere of surface area 1.25 m2 and emissivity 1.0 is at a temperature of 100C. At what rate does it radiate heat into empty space? ( = 5.67  10-8 W/m2  K4 )
 
  A) 7.1 W
  B) 0.71 mW
  C) 1.4 kW
  D) 9.9 mW
  E) 3.7 W

[javimendoza7]

Answer to Question 1

E

Answer to Question 2

C