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 ▸A rock has a mass of 100g and it is thrown across a pond at a speed of 30ms^-1. Calculate the de Broglie wavelength of the rock and explain whether you can see the wave produced.
In the photoelectric effect, what happens as you increase the frequency of light keeping the same intensity constant?
Explain how a standing wave is formed
What is EMF? How do we test for it?