What device was invented because of Faraday’s leap?

An ambulance emits a frequency of 450 hz from its siren. what frequency is heard by a man as the ambulance moves toward him? less than 450 hz more than 450 hz 450 hz 0 hz

Ababy stroller is a rest on top of a hill which is 10 m high. the stroller and baby have a mass of 20 kg. what is the potential energy of the baby and stroller?

Two technicians are discussing a resistance measurement between the can-h and can-l wires. technician a says this measurement should be done with the ignition switch in the "run" position. technician b states that a measurement of 0 ohms indicates an open in the network. which technician is correct?