The resistance of a galvanometer is 50 ohm and the maximum current which can be passed through it is 0.002 A. What resistance must be connected to it in order to convert it into an ammeter of range 0 – 0.5 A ?

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 :