Explain the following.
a. Why is the tungsten used almost exclusively for filament of electric lamps?
Tungsten is commonly used as a filament in electric bulbs because of its properties. Those are
(i) It has .
(ii) It has a .
(iii) It is not easily .
b. Why are alloys used instead of pure metals in the heating elements of devices like toasters and irons?
The conductors of electric heating devices are made of alloys rather than a pure metal because it has , and are not easily .
and is preferred as a heating element in electrical appliances such as bread-toasters and electric irons.