The current when the light bulb normally emits light: I = PU = 3.8W, 8V = 0.475A = 475 Ma. Which ammeter should I choose? a2；

The resistance of light bulb in normal light emission is about: r = u2p = 823.8 ≈16.84Ω, the internal resistance of ammeter is about 0.3Ω, and the internal resistance of voltmeter is about 4Ω.

The internal resistance of voltmeter is much larger than that of bulb. The ammeter should be externally connected, and the ammeter should be externally connected. Due to shunt of voltmeter, the measured value of ammeter is too large, and the image shown in Figure ② is accurate.

So the answer is: A2, ②.