The emf induced in a coil is given by the equation:
emf = -N dΦ/dt
Where N is the number of turns in the coil, Φ is the magnetic flux through the coil, and dt is the change in time.
When the magnet is dropped from a height h through the coil, it induces a changing magnetic flux through the coil. As the magnet enters the coil, the flux through the coil increases, and as the magnet exits the coil, the flux through the coil decreases. The rate of change of the magnetic flux through the coil is therefore maximum at the moment the bottom of the magnet enters the coil and at the moment the top of the magnet leaves the coil.
The emf induced in the coil is proportional to the rate of change of the magnetic flux. Therefore, the ratio of the emf induced in the coil at the moment the bottom of the magnet enters the coil to the emf induced in the coil at the moment the top of the magnet leaves the coil is equal to the ratio of the rate of change of the magnetic flux at these two moments.
Since the magnet is of length 1, the rate of change of the magnetic flux is the same at both ends of the magnet. Therefore, the ratio of the emf induced in the coil at the moment the bottom of the magnet enters the coil to the emf induced in the coil at the moment the top of the magnet leaves the coil is 1:1 or simply 1.