Final answer:
The energy of an electron in hydrogen at n=1 is -13.6 eV. For an unspecified energy level n=t, the energy is -13.6 eV/t^2. Thus, the answer includes E1 and Et, indicating the energies associated with the ground state and an unknown level t.
Step-by-step explanation:
The student has asked how to determine the energy associated with an electron in hydrogen at n=1 and at an unspecified level n=t. According to the Bohr model for the hydrogen atom, the energy levels are defined by the formula En = -13.6 eV/n2, where En is the energy in electron volts at a principal quantum number n. For the ground state (n=1), this energy is simply E1 = -13.6 eV, since the atomic number Z for hydrogen is 1.
For an unspecified level n=t, the energy is Et = -13.6 eV/t2. To answer the student's question, we use part (a) of the answer choices: E1 and Et, since Et would refer to the energy at a principal quantum level t.