The circuit diagram shows a relay used to control a mains lamp. The two ammeters are marked P and Q. The variable resistor is there to change the current in the relay coil. The mains lamp turns on when the current in the relay coil is large enough. The graph shows how the reading on ammeter Q varies as the reading on ammeter P increases. What is the smallest current required in the relay coil to turn on the mains lamp?
- A$0.15\,\text{A}$
- B$0.20\,\text{A}$
- C$0.35\,\text{A}$
- D$0.60\,\text{A}$