A metal wire of resistance 3 $$\Omega $$ is elongated to make a uniform wire of double its previous length. This new wire is now bent and the ends joined to make a circle. If two points on this circle make an angle 60° at the centre, the equivalent resistance between these two points will be :-

In a conductor, if the number of conduction electrons per unit volume is 8.5 × 10²⁸ m^–3 and mean free time is 25ƒs (femto second), it's approximate resistivity is :-
(m_e = 9.1 × 10^–31 kg)

A moving coil galvanometer has resistance 50$$\Omega $$ and it indicates full deflection at 4mA current. A voltmeter is made using this galvanometer and a 5 k$$\Omega $$ resistance. The maximum voltage, that can be measured using this voltmeter, will be close to :

A wire of resistance R is bent to form a square ABCD as shown in the figure. The effective resistance between E and C is : (E is mid-point of arm CD)