What is the commercial unit of electric energy?

What is meant by "electrical resistance" of a conductor? State how the resistance of a conductor is affected when $(i)$ a low current passes through it for a short duration; $(ii)$ a heavy current passes through it for about $30$ seconds.

How will you conclude that the same potential difference (voltage) exists across three resistors connected in a parallel arrangement to a battery?

State the factors on which the resistance of a cylindrical conductor depends. How will the resistance of a conductor change if it is stretched so that its length is doubled?

$A$ 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.

When do we say that the resistors are connected in parallel?