In the given circuit diagram a voltmeter 'V' is connected across a lamp 'L'. How would (i) the brightness of the lamp and (ii) voltmeter reading 'V' be affected, if the value of resistance 'R' is decreased?

The given figure is a Common Emitter(CE) configuration of an npn transistor. The input circuit is forward biased and the collector circuit is reverse biased. If resistance R decreases, the forward bias in the input circuit will increase, thus the base current IB will increase and the emitter current IE will increase. This will increase the collector current IC as IE = IC + IB. When IC increases, which flows through the lamp, the voltage across the bulb will also increase, making the lamp brighter. Since the voltmeter is connected in parallel with the lamp, the reading in the voltmeter will also increase.