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 ▸Why is the refractive index of water bigger than that of air?
What path would a charge moving in the x-y plane track, in the presence of a uniform magnetic field out of the page?
Draw a diagram of the forces acting on the rocket as it flies vertically upwards, the rocket is flying through air not a vacuum (it's not in space yet!)
Determine an approximate value for the acceleration of free fall using a tennis ball, metre ruler and a stopwatch.