Ohm's Law

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?

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

Two wires of equal length and equal cross-section are with resistivity ${\rho }_1, {\rho }_2$ are connected in a series. The equivalent resistivity of combination is

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

Three equal resistances are connected as shown in the figure. Maximum power that can be dissipated by each resistance is 40 watt. Therefore, the maximum power that can be safety dissipated in the combination is:

I1 is reading of ammeter if switches X and Y are open and I2 is reading when switches are closed.

The V-I graph for a good conductor makes angles 42° with Y-axis. Here V denotes voltage and I denotes current. Then the resistance of the conductor will be

A wire of resistance 1 ohm is stretched so as to change its diameter by 0.25%. The percentage change in its resistance is

If an equilateral triangle is made of a uniform wire of resistance R, the equivalent resistance between the ends of sides is

If equivalent resistances of R1 and R2 in series and parallel be r1 and r2 respectively, then $\frac{R_1}{R_2}$ equal

If the variable resistances are connected to a cell of constant e.m.f. then which of the following graph represents the relationship between current I and resistance R?

If reading of ammeter is 2A then what is value of X in ohm's?

For a metallic conductor, voltage versus current graph is drawn at two different temperatures T1 and T2. From the graph it follows :

The slope of voltage (V) versus current (I) is called

How will the reading in the ammeter A be affected if another identical bulb Q is connected in parallel to P (Fig). The voltage in the mains is maintained at a constant value.

A person connects four 1/4 $\Omega$ cells in series but one cell has its terminal reversed. The external resistance is 1 $\Omega$. If each cell has an emf of 1.5V, the current flowing is

At critical temperature, a metal offers _____ resistance to the passage of electricity.

Resistivity depends on which of the following?

Electrical resistivity of a given metallic wire depends upon: