## Step 1: Apply the Right-Hand Rule For a straight current-carrying wire, the **right-hand rule** helps determine the direction of the magnetic field around the wire: - Point the thumb of your right hand in the direction of the **conventional current** (positive to negative). - The curl of your fingers shows the direction of the magnetic field lines encircling the wire. **Explanation:** In both diagrams, the magnetic field will form concentric circles around the wire. The compass will align itself tangentially to these circles, pointing in the direction of the magnetic field at its location. --- ## Step 2: Determine Compass Needle Direction - In (a): The current is **upward**. Using the right-hand rule, at the location of the compass (to the right of the wire), your fingers will curl **into the page** (toward the east). - In (b): The current is **downward**. At the location of the compass (to the right of the wire), your fingers will curl **out of the page** (toward the west). **Explanation:** - For upward current, the magnetic field at the right side of the wire points **east**. - For downward current, the magnetic field at the right side of the wire points **west**. --- ## Final Answers - **(a):** The compass needle will point **east**. - **(b):** The compass needle will point **west**.

# Compass Needle Direction for Current-Carrying Wire ## Step 1: Apply the Right-Hand Rule For a straight current-carrying wire, the **right-hand rule** is used to find the direction of the magnetic field: - **Thumb:** Point in the direction of the **conventional current** (from positive to negative). - **Fingers:** Curl around the wire to indicate the direction of the magnetic field lines. **Explanation:** The magnetic field forms concentric circles around the wire. A compass needle, which aligns with the magnetic field, will point in the direction of these field lines. --- ## Step 2: Determine Compass Needle Direction - **(a):** Current is **upward**. - At the compass location (to the right of the wire), your fingers curl **into the page** (to the east). - **(b):** Current is **downward**. - At the compass location (to the right of the wire), your fingers curl **out of the page** (to the west). **Explanation:** - For upward current, the magnetic field to the right of the wire points **east**. - For downward current, the magnetic field to the right of the wire points **west**. --- ## Final Answers - **(a):** The compass needle will point **east**. - **(b):** The compass needle will point **west**.