What is the ratio of time periods in the $3^{rd}$ orbit of $H^{-}$ atom to the $2^{nd}$ orbit of $He^{+}$ ion?

Which of the following statements is $CORRECT$?

Which one is the wrong statement?

Consider the following statements:
$(a)$ Photon is a positively charged nuclear particle
$(b)$ Size of nucleus is very small as compared to the size of atom
$(c)$ Photoelectric effect and diffraction show particle nature of light
$(d)$ Planck's constant has same dimensions as angular momentum
The correct statements is/are:

For the given electronic transitions,which of the following statements is correct?

Which of the following graphs represents one node?