Vin = 0V or 5V

Vcc = 12V

β = 50

The desired current through the LED is 50mA and the voltage over that LED is 2.7V in that case.

Then we were asked what would happen if the npn-transistor was replaced by an n-channel MOSFET and if a Vin of 5V would still be sufficient. This is the part where I'm having trouble: How can I tell if 5V would have the desired effect without a datasheet or anything given about the MOSFET?

What I know:

With Vds is the voltage over drain-source, Vgs is the voltage over gate-source and Vt is the voltage threshold of the MOSFET.

Of course Vgs is where the 5 Volts would be applied.

- Saturation occurs when Vds >= Vgs - Vt
- ID = K(Vgs - Vt)²

Where could I start to solve this?