A potentiometer wire PQ of 1 m length is connected to a standard cell E₁. Another cell E₂ of emf 1.02 V is connected with a resistance ‘r’ and switch S (as shown in figure). With switch S open, the null position is obtained at a distance of 49 cm from Q. The potential gradient in the potentiometer wire is :

Consider four conducting materials copper, tungsten, mercury and aluminium with resistivity $$\rho $$_C, $$\rho $$_T, $$\rho $$_M and $$\rho $$_A respectively. Then :

In the given circuit diagram, a wire is joining points B and D. The current in this wire is :

A galvanometer having a coil resistance 100 $$\Omega $$ gives a full scale deflection when a current of 1 mA is passed through it. What is the value of the resistance which can convert this galvanometer into a voltmeter giving full scale deflection for a potential difference of 10 V?