Electrons are accelerated toward the anode by the potential difference applied across the tube.

In fusion the mass of the product is less than the sum of the reactants (mass defect) with the missing mass released as energy, so m3 < m1 + m2.

The electron mass is about 5.486×10^-4 u, commonly rounded to 0.00055 u, matching option (c).

Header indicates option D; the block provides the options and the answer marker in the OCR metadata specifies D.

Foods commonly contain naturally occurring radioactive isotopes such as potassium-40 and carbon-14; the OCR shows a mark by 'Both (A) and (B)'.

h/mc is the electron Compton wavelength, the standard name for that quantity.

Photon energy = 2·(rest mass energy 0.5 MeV) + kinetic energy 0.78 MeV = 1.78 MeV, so option B is correct.

The OCR shows a marker next to option A and hyperons are indeed particles heavier than protons.

The strong (nuclear) force acts between all nucleon pairs: proton-proton, neutron-neutron and neutron-proton, so 'all of these' is correct.

The energy of the n=3 level is -13.6/9 ≈ -1.51 eV, so its excitation (ionization from n=3) corresponds to about 1.51 eV.