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 ▸An object orbits Earth at an altitude of 200 kilometers above the planet’s surface. What is its speed and orbital period?
An alpha particle is accelerated with 5MeV of kinetic energy towards the nucleus of a gold atom with atomic number 79. What is the distance of closest approach that is reached by the alpha particle?
A sigma0 particle with mass 1193 MeV/c^2 decays into a lambda0 particle with mass 1116 MeV/c^2 a photon. Find the energy and momentum of the photon, assuming that the kinetic energy of the lambda0 particle is negligible.
When a particle travels in a circle of radius r, at constant speed v, what is its acceleration