This is a question from class 12 Physics NCERT Part 1:
I am having so much trouble with this, I can't figure out where I'm going wrong. I solved part (a) here:
(a) U= -27.2 eV
(b) Here, the kinetic energy is given to be half of the potential energy, and kinetic energy is always positive, therefore, K= +13.6 eV Total energy= -27.2 +13.6 = -13.6 eV
Now this is where I'm going wrong. To free an electron, the final potential energy must be zero and also work done is change in potential energy. From that, W= 0- (-27.2) = +27.2 eV. But the answer is +13.6 eV according to my book. What am I doing wrong?
(c) In this part,
U= (U at 0.53 Å) – (U at 1.06 Å)
U= -27.2 eV -(-13.6eV)
U= -13.6 eV
therefore, K= +6.8 eV
and, Total energy= -13.6 +6.8 = -6.8 eV
But my book says that the total energy here is zero. How? Sorry for this long question, but I've been trying to solve this for so long. Any help is appreciated. Thank you so much.