in a collector to base bias circuit using pnp BC 558 , what happened if a capacitor of 10pF connected across base and collector ? Rb=1M, Rc= 4.7k, Vcc=9V.

 

The highest frequency of amplification will change.

Where are you getting these questions?
Is this homework?

 

this is part of my project.. two stage amplification includes RC coupled amplifier and collector to base bias circuit.. in the collector to base bias circuit , 10 pF capacitor is connected and the output from collector is given to a divide by 10 counter as clock. thats why iam asking the advantage of 10pF capacitor. here frequency will be 40kHz

 

Your transistor is not biased properly so it probably won't work in your circuit.