Respuesta :

tonb
1. 3 times the light voltage, ie., 3*0.5 = 1.5V
2. Total R = 3*25 = 75Ω, V=1.5V, I = V/R = 1.5/75 = 20 mA
3. A 1.5V battery (e.g., an AA battery) with a charge of at least 20mAh. AA batteries should be able to handle this easily.