Resistances of $6\, \Omega$ each are connected in the manner shown in the adjoining figure. With the current $0.5\, A$ as shown in the figure, the potential difference $V_P - V_Q$ is .............. $V$.

In the given circuit, the current flowing through the resistance $20 \, \Omega$ is $0.3 \, A$, while the ammeter reads $0.8 \, A$. What is the value of $R_1$ in $\Omega$?

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:

An electric bulb rated $500 \, W$ at $100 \, V$ is used in a circuit having a $200 \, V$ supply. Calculate the resistance $R$ to be connected in series with the bulb so that the power delivered by the bulb is $500 \, W$. (in $\Omega$)

An electric kettle has two heating coils. When the first coil is switched on, the tea boils in $6$ minutes. When the second coil is switched on, it boils in $8$ minutes. If both coils are connected in series and switched on, how long will it take for the tea to boil?

$A$ copper voltameter is connected to a $12 \, V$ source,and $2 \, g$ of copper is deposited in $30 \, min$. If this cell is connected to a $6 \, V$ source,how much copper (in $g$) will be deposited in $45 \, min$?