$(a)$ What are the values of $mA$ and $\mu A$ in terms of Ampere $(A)$?
$(b)$ Draw the symbols of a battery and a rheostat.

Define electric current and state its $SI$ unit. With the help of $Ohm's$ law,explain the meaning of $1$ ohm resistance.

In the circuit diagram shown,the two resistance wires $A$ and $B$ are of the same area of cross-section and same material,but $A$ is longer than $B$. Which ammeter,$A_{1}$ or $A_{2}$,will indicate a higher reading for current? Give a reason.

In the process of electroplating a chromium coating onto an iron spoon,where should the chromium rod be connected?

What is meant by an electric circuit? Draw a circuit diagram to show an electric circuit comprising a battery of two cells,a resistor,an ammeter,and a plug key when the circuit is closed.

Find out the following in the electric circuit given in the figure:
$(a)$ Effective resistance of two $8\,\Omega$ resistors in the combination.
$(b)$ Current flowing through the $4\,\Omega$ resistor.
$(c)$ Potential difference across the $4\,\Omega$ resistor.
$(d)$ Power dissipated in the $4\,\Omega$ resistor.
$(e)$ Difference in ammeter readings,if any.