09:03Transformers - working & applications (step up and step down) | A.C. | Physics | Khan AcademyKhan Academy India - English270
Multiple ChoiceAn outlet in North America outputs electricity at 120 V, but a typical laptop needs to operate at around 20 V. In order to do so, a transformer is placed in a laptop's power supply. If the coil in the circuit connected to the laptop has 20 turns, how many turns must the coil in the circuit with the outlet have?26412Has a video solution.
Multiple ChoiceA transformer has 200 turns in the primary and 25 turns in the secondary. If the primary is hooked up to a 120V household outlet, what is the potential across the secondary coil?145
Textbook QuestionElectricity is distributed from electrical substations to neighborhoods at 15,000 V. This is a 60 Hz oscillating (AC) voltage. Neighborhood transformers, seen on utility poles, step this voltage down to the 120 V that is delivered to your house. a. How many turns does the primary coil on the transformer have if the secondary coil has 100 turns?
Textbook QuestionElectricity is distributed from electrical substations to neighborhoods at 15,000 V. This is a 60 Hz oscillating (AC) voltage. Neighborhood transformers, seen on utility poles, step this voltage down to the 120 V that is delivered to your house. b. No energy is lost in an ideal transformer, so the output power P out from the secondary coil equals the input power Pin to the primary coil. Suppose a neighborhood transformer delivers 250 A at 120 V. What is the current in the 15,000 V line from the substation?
