Resistance of a conductor increases (or decreases) with increase (or decrease) in the length of the conductor.
Resistance of a conductor decreases (increases) with increase (decrease) in the area of cross-section of the conductor.
Resistance of a conductor increases on raising the temperature and decreases on lowering the temperature.
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The electrical resistivities of five substances A, B, C, D and E are given below:
$\begin{matrix}\text{B}&110\times10^{-8}\Omega\text{ m}\\\text{C}&2.60\times10^{-8}\Omega\text{ m}\\\text{D}&10.0\times10^{-8}\Omega\text{ m}\\\text{E}&1.70\times10^{-8}\Omega\text{ m}\end{matrix}$
Two exactly similar electric lamps are arranged (i) in parallel, and (ii) in series. If the parallel and series combination of lamps are connected to 220V supply line one by one, what will be the ratio of electric power consumed by them?
The electrical resistivities of four materials $A, B, C$ and $D$ are given below:
$\text{A}\ -110\times10^{-8}\Omega\text{ m}$
$\text{B}-\ 1.0\times10^{10}\Omega\text{ m}$
$\text{C}-\ 10.0\times10^{-8}\Omega\text{ m}$
$\text{D}-\ 2.3\times10^{3}\Omega\text{ m}$
Which material is:
An electric iron is connected to the mains power supply of $220V$. When the electric iron is adjusted at ‘minimum heating’ it consumes a power of $360W$ but at ‘maximum heating’ it takes a power of $840W$. Calculate the current and resistance in each case.
A resistor of 8 ohms is connected in parallel with another resistor X. The resultant resistance of the combination is 4.8 ohms. What is the value of the resistor X?
What will be the resistance of a metal wire of length $2$ metres and area of cross-section $1.55 \times 10m $, if the resistivity of the metal be $2.8 \times 10 m?$
An electric bulb is rated as 10W, 220V. How many of these bulbs can be connected in parallel across the two wires of 220V supply line if the maximum current which can be drawn is 5A?