A prisoner tries to escape from a Nashville, Tennessee prison by hiding in the laundry truck. The prisoner is surprised when the
truck is stopped at the gate. A guard enters the truck and handcuffs him. "How did you know I was here?" the prisoner asks. "The heartbeat detector," says the guard.A heartbeat detector senses the tiny vibrations caused by blood pumped from the heart. With each heartbeat, blood is pumped upward to the aorta, and the body recoils slightly, conserving the momentum of the blood-body system. The body's vibrations are transferred to the inside of the truck. Vibration sensors on the outside of the truck are linked to a geophone, or signal amplifier, attached to a computer. A wave analyzer program in the computer compares vibration signals from the truck to wavelets produced by heartbeat vibrations. The wave analyzer distinguishes a person's heartbeat from other vibrations in the truck or in the surrounding environment, allowing guards to detect the presence of a human in the truck.What does the heartbeat detector sense?1-Electric signals caused by electric dipole charges produced on the heart.2-Body vibrations caused by blood pumped from the heart.3-Sound caused by breathing.4-Slight uncontrollable reflexive motions of an enclosed person.5-All of the above
Faraday's law gives the relationship between the induced emf and the rate of change of magnetic flux i.e.
The given statement "A large magnetic flux change through a coil must induce a greater emf in the coil than a small flux change" is false. The reason is that if the rate of change of magnetic flux is greater, then its will induce more emf. It would mean it does not say about emf.
