Which of the following acts as a circuit protection device?

Three resistors $1 \Omega, 2 \Omega$ and $3 \Omega$ are connected to form a triangle. Across the $3 \Omega$ resistor,a $3 \text{ V}$ battery is connected. The current through the $3 \Omega$ resistor is: (in $\text{ A}$)

In the circuit shown in the figure below,which of the following statements is incorrect?

In the circuit shown,the thermal power dissipated in $R_1$ is $P$. The thermal power dissipated in $R_2$ is

For the network of resistors shown in the figure,choose the correct option.

$A$ voltmeter of resistance $998\ \Omega$ is connected to a cell of $emf$ $2\ V$ and internal resistance $2\ \Omega$. The error in the measurement of $emf$ will be: