Ohm's Law

Electrical wires are usually made by copper. Which properties of copper make it a suitable choice-

I) High electrical conductivity
II) Sonority
III) Ductility
IV) Metallic lustre

The circuit below consists of a variable resistor connected in series with two $2000 \mathrm{\Omega }$ resistors. The variable resistor can be adjusted to any value between $0 - 4000 \mathrm{\Omega }$.

As the resistance of the variable resistor is changed, what is the smallest possible reading on the voltmeter?

State ohms law with graphical representation.

Two wires P and Q are made from the same material. Wire P and Q has a length in the ratio of $18:12$ and having a cross-sectional area in the ratio of $4:3$. Then the ratio of their resistances is:  

An electrical circuit was set up as shown below. Find the current flowing through each of the resistances in the circuit.

A cylindrical conductor of length $l$ and uniform area of cross-section $A$ has resistance $R$. Another conductor of length $2.5 l$  and resistance $0.5 R$ of the same material has area of cross-section:

List out the material required for the experiment 'The effect of increasing of section of a conductor upon its resistance" and write the experimental procedure.

Which one of the following is NOT correct for Ohm's law?

The critical temperature for superconductors is the temperature at which the electrical resistivity of a metal

A student carries out an experiment and plots the V-I graph of three samples of nichrome wire with resistance and respectively. Which of the following given condition is true?

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 :

$\mathrm{V}-\mathrm{I}$ graph for parallel and series combinations for two identical resistors are as shown in figure.Which graph represents parallel combination?

For a cell, a graph is plotted between the potential difference $V$ across the terminals of the cell and current $I$ drawn from the cell (see fig.) The emf and internal resistance of the cell are $E$ and $r$ respectively, then :

Conductivity of superconductors is

Determine the potential difference between ends of a wire of resistance $5 \mathrm{\Omega }$, if $720 \mathrm{C}$ charge passes through it per minute.

Consider an infinite grid with square cells. The resistance between two adjacent joints is $R.$ Find the net resistance $R_{net}$ of the whole grid between two points A & B.

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 rheostat shown in the figure is $0-30 \mathrm{\Omega }$, Neglecting the resistance of ammeter and connecting wire the minimum and maximum currents through the ammeter will be

In the given circuit the voltmeter reads 5V. The resistance of the voltmeter in Ohm is.