According to Bohr theory, which of the following transition in hydrogen atom will give rise to the least energetic proton?

According to Bohr's theory

According to the Bohr theory, which of the following transitions will give rise to the most energetic photon? qquad (a) ["n=4" to "n=2], b)[n=5" to "n=4], c) n=3 to n=1 d)[n=6" to "n=5]

According to Bohr's atomic theory, which of the following is correct ?

The ionisation of hydrogen atom would give rise to