Advertisements
Advertisements
प्रश्न
Plot a graph showing the variation of resistivity of a conductor with temperature.
उत्तर
The resistivity of a metallic conductor is given by
\[\rho = \rho_0 \left[ 1 + \alpha\left( T - T_0 \right) \right]\]
\\text { [where }\]
\[ \rho_0 = \text { Resistivity at reference temperature }\]
\[ T_0 =\text { Reference temperature }\]
\[ \alpha = \text { Coefficient of resistivity }\]
From the above relation, we can say that the graph between resistivity of a conductor with temperature is a straight line. But, at temperatures much lower than 273 K ( i.e. \[0 °C\], the graph deviates considerably from a straight line as shown below.
APPEARS IN
संबंधित प्रश्न
plot a graph showing the variation of current density (j) versus the electric field (E) for two conductors of different materials. What information from this plot regarding the properties of the conducting material, can be obtained which can be used to select suitable materials for use in making (i) standard resistance and (ii) connecting wires in electric circuits?
A closed surface S is constructed around a conducting wire connected to a battery and a switch in the following figure. As the switch is closed, the free electrons in the wire start moving along the wire. In any time interval, the number of electrons entering the closed surface S is equal to the number of electrons leaving it. On closing the switch, the flux of the electric field through the closed surface
(a) is increased
(b) is decreased
(c) remains unchanged
(d) remains zero
A charge Q is placed at the centre of an uncharged, hollow metallic sphere of radius a. (a) Find the surface. (b) If a charge q is put on the sphere, what would be the surface charge densities on the inner and outer surfaces? (c) Find the electric field inside the sphere at a distance x from the centre in the situations (a) and (b).
Find the magnitude of the electric field at a point 4 cm away from a line charge of density 2 × 10-6 Cm-1.
Three identical metal plates with large surface areas are kept parallel to each other as shown in the following figure. The leftmost plate is given a charge Q, the rightmost a charge −2Q and the middle one is kept neutral. Find the charge appearing on the outer surface of the rightmost plate.
Some equipotential surface is shown in the figure. What can you say about the magnitude and the direction of the electric field?
An electric field of magnitude 1000 NC−1 is produced between two parallel plates with a separation of 2.0 cm, as shown in the figure. (a) What is the potential difference between the plates? (b) With what minimum speed should an electron be projected from the lower place in the direction of the field, so that it may reach the upper plate? (c) Suppose the electron is projected from the lower place with the speed calculated in part (b). The direction of projection makes an angle of 60° with the field. Find the maximum height reached by the electron.
A uniform field of 2.0 NC−1 exists in space in the x-direction. (a) Taking the potential at the origin to be zero, write an expression for the potential at a general point (x, y, z). (b) At which point, the potential is 25 V? (c) If the potential at the origin is taken to be 100 V, what will be the expression for the potential at a general point? (d) What will be the potential at the origin if the potential at infinity is taken to be zero? Is it practical to choose the potential at infinity to be zero?
