A spotlight has a power rating of 60 W when operating at its normal working voltage.
Calculate the amount of electrical energy transferred to the spotlight in 12 hours.
A student notices that the spotlight becomes warm after it has been switched on for some time. They conclude that the spotlight cannot be 100% efficient. Explain whether the student’s conclusion is correct.
The spotlight is designed to run on a lower voltage than the mains supply, so a step-down transformer is used. Describe the structure of a step-down transformer.
The step-down transformer reduces the voltage from 240 V to 24 V. The secondary current of the transformer is 2.5 A. State the equation linking input power and output power for a transformer, assuming 100% efficiency.
Calculate the primary current.
