The process of adding impurities to a semiconductor material to increase its conductivity is 

A load of 300N is to be lifted by a machine with a velocity ratio of 2 and an efficiency of 60%. What effort will be applied to lift the load?

The average translational kinetic energy of gas molecules depends on 

The fourth overtone of a closed pipes is 900Hz, its fundamental frequency is 

A cell of internal resistance of 2\(\Omega\) supplies current through a resistor, X if the efficiency of the cell is 75%, find the value of X.