Controlling Temperature in Household Appliances

The device used to regulate temperature in household appliances is called a:

• Thermometre

• Thermostat

• Temperature Gauge

The main component in a thermostat is a:

• Temperature Setting Knob

• Bimetallic Strip

• Contact Screw

True or false, a bimetallic strip is made of two metals with different expansion coefficient.

• True

• False

The device in the photograph represents different types of:

• Thermostats

• Thermometre

• Testers

Which of the following explanation gives the correct reason for the bimetallic strip bending upward after heating?

• the side of the strip facing the heat has a higher expansion coefficient

• the side of the strip facing the heat has a lower expansion coefficient

• the strip is not being heated properly

The bimetallic strip in the photograph bends downward because:

• The metal with the lower expansion coefficient is on the upper side of the bimetallic strip.

• The metal with the higher expansion coefficient is on the upper side of the bimetallic strip.

• the flame is very close to the strip

Brass expands faster than steel when heated. In the photograph, which side of the labelled strip correctly represents these two metals:

• X - brass Y - steel

• X - steel Y - brass

Brass expands faster than steel when heated. Bimetallic strip returns to its original shape (straightens) after removing the flame because:

• steel contracts faster than brass

• brass contracts faster than steel

• both contracts at the same rate

True or false, in a cooling appliance the bimetallic strip is positioned so that the metal having the lower expansion coefficient faces the temperature setting knob?

• true

• false

Thermostats functions on the principle that:

• some metals expands and contracts at different rates

• all metal expands and contracts at different rates

• all metals expands and contracts at the same rates