Diode testing

Use the Multi meter to check flow
Swap LED's terminal if LED doest work.
Lose one terminal of LED, connect to Multi meter, make current flow through the Multi meter.

1) Voltage drop across Resistor and Diedo.
2) Amp flow the diedo
3) Bolyshr sy poert supply
4) Add the voltage drop from Resistor and diedo.

we got : A] 0.1V at resistor and 11.9V at diedo

             B] 0.03A at diedo.

             C] 12V at power supply.
             D]11.9V at diedo and 0.1V at Resistor.