We're given this diagram with a question and asked: (NPN transistor) a) Describe what would happen when the circuit is switched on. b) Explain why this happens. c) What is the time constant for the capacitor in this circuit? d) What is the purpose of the 50k ohm resistor? I'm having problems answering a. If the voltage across the base and emitter >= 0.6A, THEN the lamp would be lit.. However, I have ABSOLUTELY NO CLUE how to find the voltage across the base and emitter! Can someone show me how? (I never learnt this in class, with respect to transistors :() Thanks.