An electric bulb rated as $200 \, W$ at $100 \, V$ is used in a circuit having $200 \, V$ supply. The resistance $R$ that must be put in series with the bulb so that the bulb delivers the same power is $..... \, \Omega$.

Calculate the current shown by the ammeter $A$ in the circuit diagram. (in $A$)

Which arrangement of four identical resistances should be used to draw maximum energy from a cell of voltage $V$?

Two resistances of $400 \Omega$ and $800 \Omega$ are connected in series with a $6 \text{ V}$ battery of negligible internal resistance. $A$ voltmeter of resistance $10000 \Omega$ is used to measure the potential difference across the $400 \Omega$ resistor. The error in the measurement of potential difference in volts is approximately:

In the given circuit,the current through $2 \ \Omega$ resistor is

The magnitude and direction of the current in the circuit shown will be