An electron in a metal is free to move anywhere but cannot leave the metal.
Find the number of electrons transferred between two points kept at a potential difference of $20\, V$ if $40\, J$ of work is done.
Mention two special features of the material to be used as element of an electric iron.
The filament of electric bulb is made of tungsten Why ?
A nichrome wire has a resistance of $10\, \Omega$. Find the resistance of another nichrome wire, whose length is three times and area of cross-section four times the first wire.