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 ▸Given that z = 6 is a root of the cubic equation z^3 − 10z^2 + 37z + p = 0, find the value of p and the other roots.
A body is moving at 70km/h and has a mass of 130kg, calculate its maximum kinetic energy.
The Heisenberg Uncertainty principle states that ΔxΔp > h/4π. What is represented by the terms Δx, and Δp? What can we say about p if the precise value of x is known? What does this mean for experimental results.
Water flows through an electric shower at a rate of 6kg per minute. Assuming no heat is transferred to the surroundings, what power is required to heat the water by 20K as it flow through the shower?