Why does the voltage at both ends of option D decrease? My analysis is: in Figure B, if the resistance is R and the total resistance is ignored, it is R / 3. Compared with figure B, the resistance in Figure C is 3R / 2 and the resistance increases, so the total current decreases, the voltage in the power supply decreases, the terminal voltage increases, ur1 decreases, and the voltages of R2 and D increase and are equal

Why does the voltage at both ends of option D decrease? My analysis is: in Figure B, if the resistance is R and the total resistance is ignored, it is R / 3. Compared with figure B, the resistance in Figure C is 3R / 2 and the resistance increases, so the total current decreases, the voltage in the power supply decreases, the terminal voltage increases, ur1 decreases, and the voltages of R2 and D increase and are equal

The key point is to analyze figure a clearly. Figure B tells us that when the voltage is u, the resistance of D is equal to other resistances. Now look at figure C. at this time, it is obvious that the voltage at both ends of D is less than u, so according to figure a, the resistance of D is less than the other two resistances, so the power of R2 and D is equal to UI, u is equal, the resistance of D is small, and the current I is large