Hydrogen Atom Questions

Which of the following statements in relation to the hydrogen atom is correct?

Which of the following transitions in hydrogen atoms emit photons of highest frequency?

The ionization enthalpy of hydrogen atom is $1.312\times 10^6\text{J/mol}$. The energy required to excite the electron in the atom from $n=1$ to $n=2$ is:

The transition from the state $n=4$ to $n=3$ in a hydrogen-like atom results in ultraviolet radiation. Infrared radiation will be obtained in the transition from: