please answer to all questions

Question 1 1 pts Acertain molecule has rotational inertia 4.3 x 10'47 kg m2. What is the wavelength of the emitted photon when this molecule undergoes a transition from thel = 7 rotational state to the the I = 2 state (with no change in vibrational state}. Give your answer in micrometres {pm}. Question 2 1 pts A lightemitting diode {LED} generates photons as electrons move across the PN junction. dropping from the conduction band into holes in the valence band. The energy of the emitted photons matches the band gap energy of the semiconductor material. Your friend has developed a new semiconductor material with a band gap energy of 4.3 eV. If you use this material to construct a lightemitting diode. what wavelength will it emit? Give your answer in nanometres (nml. Question 3 1 pts Calculate the number of halflives required for a radioactive sample's activity to reduce to only 22% of its original value. Give your answer to 2 decimal places (Le. it is unlikely to be an integer number of halflives).