请解答这道题---10. 「2024 天津南开期末, ✭✭] 如图所示, 是某实验电路的一部分, 电流表的示数如图所示为____A, 若通过导线 ab 的电流大小为 0.3 A, 电流方向为 a→b, 则通过导线 cd 的电流是____A。 **Diagram Description:** Type: Ammeter dial and circuit connection schematic. Ammeter Dial: - Scale Range: Upper scale from 0 to 3, lower scale from 0 to 0.6. - Markings: Upper scale has major divisions at 0, 1, 2, 3. Lower scale has major divisions at 0, 0.2, 0.4, 0.6. Both scales have finer subdivisions. - Pointer: The pointer is on the lower scale (0-0.6A range), pointing to the third mark after 0.4. - Terminals: Labeled '0' (negative), '0.6' (positive), and '3' (positive). Terminals '0' and '0.6' are indicated as connected to the circuit points. Circuit Snippet: - Points: Labeled a, b, c, d. - Connections: Point 'a' is connected to the '0' terminal of the ammeter. Point 'd' is connected to the '0.6' terminal of the ammeter. There are lines labeled 'ab' and 'cd', and a curved line from 'a' to 'c'. **Relevant Information from Diagram:** - The ammeter is connected between points 'a' and 'd', with 'a' connected to the negative terminal and 'd' to the 0.6A range positive terminal. - The ammeter reading, using the 0.6A range, is determined by the pointer position. The minor divisions on the 0.6A scale represent 0.02A (0.6A / 30 divisions = 0.02A/division). The pointer is 3 divisions past 0.4A, so the reading is 0.4A + 3 * 0.02A = 0.46A. **Other Relevant Text:** - "是某实验电路的一部分" (is part of an experimental circuit) - "电流表的示数如图所示为____A" (the ammeter reading is as shown in the figure is ____A) - "若通过导线 ab 的电流大小为 0.3 A, 电流方向为 a→b" (If the magnitude of the current through wire ab is 0.3 A, and the direction is a→b) - "则通过导线 cd 的电流是____A" (then the current through wire cd is ____A)