Electric Conductivity - Practice Questions & MCQ

The effect of increase in temperature on the number of electrons in conduction band  and resistance of a semiconductor will be as:

Copper has face centered cubic (fcc) lattice with interatomic spacing equal to. The value of lattice constant for this lattice is

A potential difference of 2V is applied between the opposite faces of a Ge crystal plate of area and thickness 0.5 mm. If the concentration of electrons in Ge is  and mobilities of electrons and holes are 

 respectively, then the current flowing through the plate will be

The resistivity of pure silicon is and the mobilities of electrons and holes in it are 0.135 and -s respectively. The resistivity of a specimen of silicon doped with  atoms of phosphorus per meter is:  

When plate voltage in diode valve is increased from  to  then plate current increases from  to . The dynamic plate resistance will be

The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than 2480 nm, is incident on it. The band gap in (eV) for the semiconductor is

A piece of copper and another of germanium are cooled from room temperature to 77 K, the resistance of 

For a given plate-voltage, the plate current in a triode is maximum when the potential of

A metallic surface with work function of , on heating to a temperature of  gives an emission current of  If another metallic surface having the same surface area, same emission constant but work function   is heated to a temperature of , then the emission current will be

A potential difference of  is applied between the opposite faces of a Ge crystal plate of area  and thickness. If the concentration of electrons in G eis   and mobilities of electrons and holes are respectively, then the current flowing through the plate will be