A compass needle placed just above a wire in which electrons are moving towards west, will point

Options

A. east
B. north
C. west
D. south

Answer

To determine the direction in which a compass needle will point when placed just above a wire carrying current, we can follow these steps:

### Step 1: Identify the Direction of Electron Flow
In the given scenario, electrons are moving towards the west.

### Step 2: Determine the Direction of Conventional Current
Since electrons have a negative charge and flow in the opposite direction to conventional current, the flow of current will be towards the east (opposite to the direction of electron flow).

### Step 3: Apply the Right-Hand Thumb Rule
To find the direction of the magnetic field created by the current, we can use the right-hand thumb rule:
- Point your right thumb in the direction of the conventional current (which is towards the east).
- Curl your fingers around the wire.

### Step 4: Analyze the Magnetic Field Direction
As you curl your fingers, the direction of your fingers will indicate the direction of the magnetic field lines. When your thumb points east, your fingers will curl upwards above the wire.

### Step 5: Determine the Compass Needle Direction
A compass needle aligns itself with the magnetic field lines. Since the magnetic field above the wire is directed upwards, the north pole of the compass needle will point towards the north.

### Conclusion
Therefore, the compass needle placed just above the wire will point towards the north.

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