Current Electri...

The four wires from a larger circuit intersect at junction A a shown. What is the magnitude and direction of the current between points A and B?

The resistance of a copper wire and an iron wire at 20C are 4.$$\Omega $$ and 3.9$$\Omega $$ respectively. Neglecting any thermal expansion, find the temperature at which resistances of bolh are equal. 
$$\alpha _{ cu }=4.0\times { 10 }^{ -3 }{ K }^{ -1 }$$. and $$\alpha _{ fe }=4.0\times { 10 }^{ -3 }{ K }^{ -1 }$$.

Two wires of same metal have the same length but their cross-sections are in the ratio 3:1. They are joined in series. The resistance of the thicker wire is $$10\Omega$$. The total resistance of the combination is:

The resistance of a wire at room temperature $$30^oC$$ is found to be $$10\Omega$$. Now to increase the resistance by 10%, the temperature of the wire must be: [The temperature coefficient of resistance of the material of the wire is 0.002 per $$^oC$$]

In an experiment to measure the internal resistance of a cell by a potnetiometer, it is found that the balance point is at a length of 2 m, when the cell is shunted by a 5 $$\Omega$$ resistance; and is at a length of 3 m, when the cell is shunted by a 10 $$\Omega$$ resistance. The internal resistance of the cell is, then

A bulb is connected to a cell. How is the resistance of circuit affected if another identical bulb is connected in series ?

A potentiometer consists of a wire of length 4m and resistance 10$$\Omega$$. It is connected to a cell of e.m.f. 3V. The potential gradient of wire is

Value of Current i in the following circuit is :-

Which device is used to measure the potential difference between two points of a conductor in the laboratory?

The principle involved in potentiometer is