List I (electronic device) | List-II(Use/application) | ||
---|---|---|---|
A | Photodiode | I | Remote controls |
B | Zener diode | II. | Amplifier |
C | Light emitting diode | III | Voltage regulator |
D | Transistor | IV | Photodetector |
Two point charges +q and −q are held at (a, 0) and (−a, 0) in x-y plane. Obtain an expression for the net electric field due to the charges at a point (0, y). Hence, find electric field at a far off point (y ≫ a).