In the given circuit, a voltmeter ‘V’ is connected across a bulb ‘B’. If the resistor ‘R’ is increased in value?

The reverse biasing results in very high resistance across the p-n junction. If the value of the resistance R is increased, the current in the forward biased input circuit decreases. The emitter current I_E decreases and hence the collector current $(I_C = I_E – I_B)$also decreases. The glowness of the bulb decreases. Due to decrease in IC, the potential drop across the bulb B decreases and hence the voltmeter shows a lower voltage.