Question

What kind of detector contains a small radioactive source that is used to charge the air inside a small chamber. The charged air allows a small current to cross through the chamber and complete an electrical circuit. When smoke enters the chamber, it shields the radiation, which stops the current and triggers an alarm?

a) Ionization detector
b) Photoelectric detector
c) Heat detector
d) Flame detector

Answer 1

The detector described is an ionization detector, using americium-241 to ionize air and detect smoke by a reduction in current flow.

Step-by-step explanation:

The type of detector that you are describing is known as an ionization detector. These detectors have a small radioactive source, typically americium-241, which emits alpha particles to ionize the air inside a small chamber.

This ionization process allows for a small electric current to flow between two metal plates in the detector. When particles of smoke from a fire enter the detector, they disrupt this flow of charged air particles, thus reducing the current. The drop in current triggers the detector's alarm, signaling the presence of smoke and potentially a fire.

The kind of smoke detector that contains a small radioactive source and works by charging the air inside a small chamber is called the ionization detector.

It uses a small amount of radioactive material, such as americium-241, to ionize the air between two metal plates inside the chamber. When smoke enters the chamber, it blocks the radiation, causing a drop in the current and triggering an alarm.