Calculate the speed and de Broglie wavelength of an electron that has been accelerated by a potential difference of 500 V.

 

Related Questions:

(1) Show that circumference of the Bohr orbit for hydrogen atom is an integral multiple of the de Broglie wavelength associated with the electron revolving about that orbit.

(2) Why does a moving cricket ball not show wave like nature?

Solved Questions:

(1) Calculate the energy per mole of photon of electromagnetic radiations of wavelength 4000Å.

(2) Suppose 10–17 J of light energy is needed by the interior of the human eye to see an object. How many photons of green light (wavelength =550 nm) are needed to generate this minimum amount of energy?

(3) A bulb emits light of wave length 4500Å. The bulb is rated as 150 watt and 8% of the energy is emitted as light. How many photons are emitted by the bulb per second?

Practice Questions:

1. A photon of light of wavelength 6000 Å has energy E. Calculate the wavelength of photon of a light which has energy/photon 4E.                                                            

2. Calculate the wavelength, wave number and frequency of photon having its energy 5 electron volt.

3. Iodine molecule dissociates into atoms after absorbing light of 4500Å. If one quantum of radiation is absorbed by each molecule, calculate the kinetic energy of iodine atoms. (Bond energy of I₂ = 240 kJ mol^–1)                      

Answer Keys:                                

1.     Lemda-2= 1500 Å

2.     2.475 × 10^–5 cm, 4.04 × 10⁴ cm, 1.212 × 10¹⁵ Hz

3.     2.16 × 10^–20 J