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 ▸You are asked to find the Young modulus for a metal using a sample of wire. *(a) Describe the apparatus you would use, the measurements you would take and explain how you would use them to determine the Young modulus for the metal.
Initially, trucks A and B are travelling in opposite directions. A has mass 1000 kg and is travelling at speed 7ms^-1. B has mass 4000kg and is travelling at speed 2ms^-1. What is their speed and direction after collision if they move together?
What's the difference between a bayron and a meson?
A hot air balloon is travelling at a speed of 5.0m/s at an angle of 60.0 degrees up from the horizontal. Find the vertical and horizontal components.