Preformed vitamin A occurs naturally in dairy products, eggs, fish and meat, especially liver. Carotenoids are found in bright yellow and orange vegetables such as carrots, pumpkin and sweet potatoes, broccoli and spinach.he best food sources are beef and chicken liver, whole milk, cheese, and eggs. You get vitamin A from beta-carotene in carrots, mango, sweet potato, spinach, cantaloupe, kale, apricots, red pepper, broccoli, and fortified foods.
When the switch is first closed, the voltage across the capacitor (which we were told was fully discharged) is zero volts; thus, it first behaves as though it were a short-circuit. Over time, the capacitor voltage will rise to equal battery voltage, ending in a condition where the capacitor behaves as an open-circuit.
The electricity from your body is stored in the capacitor and then sent to the phone to charge it. The coins act as a two plates of a capacitor and the air gap and the paper act as the insulator (dielectric). The paper clip is to connect inside of your usb connector to the outer plate of the capacitor. Have fun!