"Forced beta" is simply the beta value you use to force the transistor into saturation, which is typically well below the active region value.What is force beta in lecture.
How do we calculate force beta value.
For standard BJT's a forced beta of 10-20 is usually used.
You can see the value used in the data sheet where they specify the transistor saturation voltage.
The Ic value is the maximum current the transistor will switch when saturated.Beta_Force = ic/ib
and then where to get ic value :
It's determined by the load resistance and the supply voltage.
Thus, if the supply voltage was 10V and the load resistor was 100Ω, then the maximum Ic would be 100mA.