If the resistance R1 is increased (see figure), how will the readings of the ammeter and voltmeter change?

             

Hint: IB=VBB-VBERi
Step 1: Find the change in base current.
Consider the circuit in fig. (b) to find the change in readings.
As we know the formula for base current, IB=VBB-VBERi
Step 2: Find the change in the ammeter reading and the voltmeter reading.
As Ri is increased, IB is decreased.
Now, the current in ammeter is collector current IC.
IC=βIB as IB decreases IC also decreases and the reading of voltmeter and ammeter also decreases.