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 $\Omega$?

When a wire of uniform cross-section $a$,length $l$ and resistance $R$ is bent into a complete circle,what is the resistance between any two diametrically opposite points?

In the given figure,each plate of the capacitor with capacitance $C$ has a charge. Find the charge on the capacitor.

$A$ uniform metallic wire carries a current of $2\,A$ when a $3.4\,V$ battery is connected across it. The mass of the uniform metallic wire is $8.92 \times 10^{-3}\,kg$,its density is $8.92 \times 10^3\,kg/m^3$,and its resistivity is $1.7 \times 10^{-8}\,\Omega\cdot m$. The length of the wire is $l = \dots\dots\dots\dots\,m$.

What is the reading of the voltmeter in the following figure (in $V$)?

In the circuit shown below,the reading of the voltmeter $V$ is ........... (in $, V$)