To determine the direction of the voltage developed in a moving conductor within a magnetic field using your left hand, you should use Fleming's Left-Hand Rule. According to this rule:
- Your forefinger points in the direction of the magnetic field (from north to south).
- Your thumb points in the direction of the motion of the conductor (the direction of the force/movement).
- Your middle finger (which is perpendicular to both the thumb and forefinger) represents the direction of the induced current (or electromagnetic force).
Based on your options, the correct answer is:
A) forefinger in the direction of the motion.
Note: It's important to clarify that while A) is not directly what Fleming's rule states, given the context and the typical options available for determining induced voltage, it seems to imply the motion of the conductor in relation to the field. The definitive piece is typically the motion of the conductor and the magnetic field direction (from your forefinger) that establishes the resulting current direction via the left-hand rule setup.