Factors on Which the Resistance of a Conductor Depends

If a wire of $1 \mathrm{m}$ length and $10 \mathrm{\Omega }$ resistance is stretched to $3 \mathrm{m}$ length by keeping its volume intact. Now the resistance of the wire will be :

The resistance of a conductor is directly proportional to

Consider the following Assertion and the Reason and select the correct alternative: Assertion (A): Alloys are used in electric heating devices. Reason (R): Alloys do not oxidise readily at high temperature.

The resistance of a wire is $4 \mathrm{\Omega }$. If the length of the wire is made double and the area of cross-section is made half, then the new resistance will be :

In the above questions 39, when the wires are connected in parallel, the heat produced in thinner wire is H1 and that in thicker wire is H2. Which of the following is correct?

Two heating wires of equal length are first connected in series and then in parallel to a constant voltage source. The rate of heat produced in the two cases is

A cylindrical copper rod has length L and resistance R. If it is melted and formed into another rod of length $2$L, the resistance will be

Students were asked do find the equivalent resistance of circuit diagram across BC. 

Based on information given in the diagram choose the appropriate relation between the reading of V1, V2 and V3.

With decrease in temperature, resistivity of a conductor

With decrease in density of the material, the resistance of the conductor

The resistance will be least in a wire with dimensions

A wire of resistance r is cut into m equal parts. These parts are then connected in parallel. The equivalent resistance of the combination will be

A 8Q resistance wire is sent through 180° at its midpoint and the two halves are twisted together. Then the resistance (in ohm) is

A rectangular conducting cube (resistivity p) has dimensions l x b x h. When current is passed through the length side, the resistance offered by the cube is

A conductor behaves as superconductor at

If a wire of resistance R is fold n times so that its length becomes ${\left(\frac{1}{n}\right)}^{th}$ of its initial length, then its new resistance becomes

What happens to its resistivity when some impurity is added in a conductor?

If area of cross-section of a metallic wire becomes n times, its resistance becomes

If radius of a metallic wire becomes n times, its resistance becomes