Describe one technique you could use to measure the threshold voltage for LEDs.
A sensitive ammeter is placed in series with LED. With the increase in Voltage, measure the potential difference value when it starts conducting. Black-out and shaded vision tube is used to observe the voltage value when visible light is first observed as the voltage is increased.
MP
Related Physics A Level answers
All answers ▸I do 400J of work compressing a gas, but I maintain the same temperature. What is the delta U, Q and W in this case?
Two trains are heading in opposite directions on the same track. Train X has a mass of 16000kg and a speed of 2.8m/s. Train Y has a mass of 12000kg and a speed of 3.1m/s. At what speed do the joined trains move off together immediately after the collison?
What does the double slit experiment tell us about light?
A conical pendulum is a mass suspended from a point that traces out a horizontal circle. By balancing the weight with the tension in the string, determine the speed of the bob.