What is the unit of resistance?

The resistivity of semiconductor materials is $..........$.

$A$ child has drawn the electric circuit to study Ohm's law as shown in the figure. His teacher told him that the circuit diagram needs correction. Study the circuit diagram and identify the errors,then describe the correct circuit configuration.

What are the resistors used in devices like radios and televisions made of?

The units of resistance are ampere.

What is the resistance of an electric arc lamp,if the lamp uses $20\, A$ when connected to a $220\, V$ line?