if you ignore the secondary of a transformer, then you can say that the primary is just an inductor.
this inductor has an impedance determined by the number of turns and the core that the turns are wrapped around.
core size and type of steel used will determine inductance and therefore the impedance by the formula XL=2 pi f L
the higher the inductance, then the higher the impedance, but there is a catch.
in an inductor, the impedance will depend on the frequency across the inductor.
usually a transformer will have an impedance rating at a certain frequency.
reflected impedance is associated with the ratio of the transformer, not the inductance of the pri/sec.
so you have two types of impedance associated with a transformer, the first type is associated with the enviroment you are working in, ie, 150 ohm mic, 600 ohm line, 10K bridging,
usually for voltage transfer we want the transformer primary to have about 10 times the impedance of the source,
so a 600:600 might have a Reactance of 6000 ohms at 20 Hz, and a 10K might have 100K ohms of Reactance in order not to lose too much signal.
this Reactance will depend on he turns and the core. a 600:600 will have fewer turns than he 10K;10K, etc.
Reactance is just impedance related to what kind of device is creating it, Cap or Coil. both are measured in Ohms.
as mentioned above, reflected load will be a function of the load and the turns ratio,
1:1 with RL at 1K reflects 1K,
1:2 with RL at 1K reflects 2^2 = 4 so 1:4 Z ratio reflects 250 Ohms
1:4 with RL at 1K reflects 4^4 =16 so 1:16 Z ratio reflects 62.5 Ohms
1:10 = 1:100 Z = 10 ohms reflected
1:20 = 1:400 Z ratio = 2.5 ohms reflected
usually the sec of a signal transformer sits with a very Hi Z input circuit, for tubes at least,
just as you want the source to go into a 10 times load, you want the sec to go into a 10 times load, usually no a problem with tubes, so you might have a 1: 10 xfmr reflecting 100 times a 150 ohm mic, or 15K, into a grid of many megohms, so no loss of signal would be expected.
sometimes there are resonant peaks associated with a hi ratio xfmr, in which case you will see a resistor stuck on the sec to dampen this out a bit. this comes at he expense of signal current, but usually this current is in the 60 K Hz range so we do not care.