Draw a circuit diagram of an electric circuit containing a cell, a key, an ammeter, a resistor of $2 \mathrm{\Omega }$ in series with a combination of two resistors ($4 \mathrm{\Omega }$ each) in parallel and a voltmeter across the parallel combination. Will the potential difference across the $2 \mathrm{\Omega }$ resistor be the same as that across the parallel combination of $4 \mathrm{\Omega }$ resistors? Give reason.

What is electrical resistivity? In a series electrical circuit comprising a resistor made up of a metallic wire, the ammeter reads $5 \mathrm{A}$. The reading of the ammeter decreases to half when the length of the wire is doubled. Why?

$B_1$, $B_2$ and $B_3$ are three identical bulbs connected as shown in figure. When all the three bulbs glow, a current of $3 \mathrm{A}$ is recorded by the ammeter $A$. What happens to the glow of the other two bulbs when the bulb $B_1$ gets fused?

$B_1$, $B_2$ and $B_3$ are three identical bulbs connected as shown in figure. When all the three bulbs glow, a current of $3 \mathrm{A}$ is recorded by the ammeter $A$. What happens to the reading of $A_1$, $A_2$, $A_3$ and $A$ when the bulb $B_2$ gets fused?

$B_1$, $B_2$ and $B_3$ are three identical bulbs connected as shown in figure. When all the three bulbs glow, a current of $3 \mathrm{A}$ is recorded by the ammeter $A$. How much power is dissipated in the circuit when all the three bulbs glow together?