How both current and voltage values obtained at secondary of CT are in range of milli-volt/ ampere?
The voltage on the primary of the current transformer is the reflected impedance of the 7.5 Ohm burden resistor times the current .  So the primary voltage is very small, not 230V.  Most of the voltage is dropped across the load. (If the voltage across the CT were 230V, you would have zero volts across your load by KVL, right?  You need a very small CT primary impedance for small insertion loss and low power dissipation.)

Reflected impedance in a transformer results from the transformer equations you wrote-  The primary impedance will be equal to the secondary impedance (7.5 Ohms) divided by the turns ratio squared. You can derive that easily from the equations. (In a perfectly ideal transformer.)  Since the transformer is not ideal there are other factors to take into account which are detailed in the linked document.

Here's a good discussion of how CTs work: Current Transformer Theory

Equivalent circuit excerpted from link above: