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 ▸What is the difference between a scalar and a vector? Give 3 examples of each.
Given the rate of thermal energy transfer is 2.7kW, the volume of the water tank is 4.5m^3, the water is at a temperature of 28oC, density of water is 1000kgm-3 & c=4200Jkg-1K-1. Calculate the rise in water temperature that the heater could produce in 1hr
A given star has a peak emission wavelength of 60nm, lies 7.10*10^19m away and the intensity of its electromagnetic radiation reaching the Earth is 3.33*10^-8Wm^-2. Calculate the star's diameter
What is escape velocity?