A BJT with β = 50 has a base to collector leakage current I_CBO of 2.5 μA. If the transistor is connected in CE configuration, the collector current for I_B = 0 is 

Concept:

ICEO is the reverse leakage current in the common-emitter configuration of BJT when the base is open.

ICBO is the reverse leakage current in the common-base configuration of BJT when the emitter is open.

Also, ICEO > ICBO

And they are related by the relation:

ICEO = (1 + β) ICBO

Total collector current is given by:

IC = βIB + ICBO(β + 1)

Application:

The total collector current for the given configuration will be:

IC = βIB + ICBO(β + 1)   ---(1)

Given: I_B = 0 A, β = 50, and ICBO = 2.5 μA.

Substituting these values in Equation (1), we get:

IC = (50)(0) + (2.5 μ) (50 + 1)

I_C = 2.5 × 10^-6 × 51 A

IC = 0.1275 mA