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.
A capacitor acts as an open circuit after long time period, and acts as a short (or voltage source) for short time periods, given a change in voltage level. The inductor acts as a short circuit after a long time period, and acts as an open circuit (or a current source) for a short time period given a change in voltage level. The actual current that flows however is based on the initial conditions, BOTH current AND voltage.