Cutoff wavelength of X-rays coming from a Coolidge tube depends on the
Cutoff wavelength of X-rays coming from a Coolidge tube depends on the
The correct option is B Accelerating voltage
Since it is pretty clear that the lost kinetic energy of an electron gets converted into an x-ray photon, the maximum energy a photon can carry will be limited by the maximum kinetic energy an electron can gain! Due to the presence of an electric field in the Coolidge tube, the electrons will be accelerated towards the anode, gaining speed and kinetic energy with time. If the potential difference between the electrodes is set to be V , an electron will gain kinetic energy of eV units when it is close to the positive plate. If one of these electrons lose all of the gained kinetic energy in one collision with an anode atom (magnitude ofΔ K.E=eV), it will result in the highest energy x-ray (Ex.ray=eV) having the smallest, or cut-off wavelength! We see that it only depends on the accelerating voltage and nothing else!
Accelerating voltage
Since it is pretty clear that the lost kinetic energy of an electron gets converted into an x-ray photon, the maximum energy a photon can carry will be limited by the maximum kinetic energy an electron can gain! Due to the presence of an electric field in the Coolidge tube, the electrons will be accelerated towards the anode, gaining speed and kinetic energy with time. If the potential difference between the electrodes is set to be V , an electron will gain kinetic energy of eV units when it is close to the positive plate. If one of these electrons lose all of the gained kinetic energy in one collision with an anode atom (magnitude ofΔ K.E=eV), it will result in the highest energy x-ray (Ex.ray=eV) having the smallest, or cut-off wavelength! We see that it only depends on the accelerating voltage and nothing else!
