In the following circuit, the battery has an emf of $$2 \mathrm{~V}$$ and an internal resistance of $$\frac{2}{3} \Omega$$. The power consumption in the entire circuit is _________ W.

Equivalent resistance of the following network is __________ $$\Omega$$.

Two resistance of $$100 \Omega$$ and $$200 \Omega$$ are connected in series with a battery of $$4 \mathrm{~V}$$ and negligible internal resistance. A voltmeter is used to measure voltage across $$100 \Omega$$ resistance, which gives reading as $$1 \mathrm{~V}$$. The resistance of voltmeter must be _______ $$\Omega$$.

Two cells are connected in opposition as shown. Cell $$\mathrm{E}_1$$ is of $$8 \mathrm{~V}$$ emf and $$2 \Omega$$ internal resistance; the cell $$\mathrm{E}_2$$ is of $$2 \mathrm{~V}$$ emf and $$4 \Omega$$ internal resistance. The terminal potential difference of cell $$\mathrm{E}_2$$ is __________ V.