If electron, hydrogen, helium and neon nuclei are all moving with the velocity of light, then the wavelengths associated with these particles are in the order?

Q. The atoms of which of the following pair of elements are most likely to exist in free state ?
(a) hydrogen and helium
(b) argon and carbon
(c) neon and nitrogen
(d) helium and neon

Q. Assertion :Energy is released in the nuclear fusion of hydrogen nuclei to form helium nuclei. Reason: Binding energy per nucleon of helium is greater than hydrogen.

Q. Which among the following has the highest boiling point?

Q. We have two vessels of equal volume, one filled with hydrogen and the other with an equal mass of Helium. The common temperature is ${27}^{\circ }C$.
If the temperature of Helium is kept at ${27}^{\circ }C$ and that of hydrogen is changed, at what temperature will its pressure become equal to that of helium? The molecular weights of hydrogen and helium are $2$ and $4$ respectively.