Two resistors are connected in series across a battery as shown in figure. If a voltmeter of resistance 2000 $$\Omega$$ is used to measure the potential difference across 500 $$\Omega$$ resistor, the reading of the voltmeter will be ___________ V.

The variation of applied potential and current flowing through a given wire is shown in figure. The length of wire is 31.4 cm. The diameter of wire is measured as 2.4 cm. The resistivity of the given wire is measured as x $$\times$$ 10^$$-$$3 $$\Omega$$ cm. The value of x is ____________. [Take $$\pi$$ = 3.14]

For the network shown below, the value of V_B $$-$$ V_A is ____________ V.

All resistances in figure are 1 $$\Omega$$ each. The value of current 'I' is $${a \over 5}$$ A. The value of a is _________.