Advertisements
Advertisements
प्रश्न
As the temperature of a metallic resistor is increased, the product of its resistivity and conductivity ____________ .
विकल्प
increases
decreases
remains constant
may increase or decrease
Advertisements
उत्तर
As the temperature of a metallic resistor is increased, the product of its resistivity and conductivity remains constant.
Resistivity = `1/"conductivity"`
The product of resistivity and conductivity is equal to a constant.
APPEARS IN
संबंधित प्रश्न
Show variation of resistivity of Si with temperature in a graph ?
The thermal energy developed in a current-carrying resistor is given by U = i2 Rt and also by U = Vit. Should we say that U is proportional to i2 or i?
A non-ideal battery is connected to a resistor. Is work done by the battery equal to the thermal energy developed in the resistor? Will your answer change if the battery is ideal?
Sometimes it is said that "heat is developed" in a resistance when there is an electric current in it. Recall that heat is defined as the energy being transferred due to temperature difference. Is the statement in quotes technically correct?
Two resistors R and 2R are connected in series in an electric circuit. The thermal energy developed in R and 2R are in the ratio ______________ .
Is inversion temperature always double the neutral temperature? Does the unit of temperature have an effect in deciding this question?
Is neutral temperature always the arithmetic mean of the inversion temperature and the temperature of the cold junction? Does the unit of temperature have an effect in deciding this question?
As temperature increases, the viscosity of liquids decreases considerably. Will this decrease the resistance of an electrolyte as the temperature increases?
The 2.0 Ω resistor shown in the figure is dipped into a calorimeter containing water. The heat capacity of the calorimeter together with water is 2000 J K−1. (a) If the circuit is active for 15 minutes, what would be the rise in the temperature of the water? (b) Suppose the 6.0 Ω resistor gets burnt. What would be the rise in the temperature of the water in the next 15 minutes?
Find the thermo-emf developed in a copper-silver thermocouple when the junctions are kept at 0°C and 40°C. Use the data given in the following table.
| Metal with lead (Pb) |
a `mu V"/"^oC` |
b `muV"/("^oC)` |
| Aluminium | -0.47 | 0.003 |
| Bismuth | -43.7 | -0.47 |
| Copper | 2.76 | 0.012 |
| Gold | 2.90 | 0.0093 |
| Iron | 16.6 | -0.030 |
| Nickel | 19.1 | -0.030 |
| Platinum | -1.79 | -0.035 |
| Silver | 2.50 | 0.012 |
| Steel | 10.8 | -0.016 |
A carbon resistor has coloured bands as shown in Figure 2 below. The resistance of the resistor is:
figure 2
An electrical cable of copper has just one wire of radius 9 mm. Its resistance is 5 ohm. This single copper wire of the cable is replaced by 6 different well insulated copper wires each of radius 3 mm. The total resistance of the cable will now be equal to ______.
Temperature dependence of resistivity ρ(T) of semiconductors, insulators and metals is significantly based on the following factors:
- number of charge carriers can change with temperature T.
- time interval between two successive collisions can depend on T.
- length of material can be a function of T.
- mass of carriers is a function of T.
The temperature (T) dependence of resistivity of materials A and material B is represented by fig (i) and fig (ii) respectively. Identify material A and material B.
 fig. (i) |
 fig. (ii) |
