Resistivity Temperature Dependence: Definition, Unit, Temperature

Ans. For all semiconductors, resistivity reduces with an increase in temperature. With increases in temperature more electrons become loose from their atoms. A semiconductor with a negative temperature coefficient of resistance is called a thermistor.

Ans. Resistivity is inversely proportional to the temperature. Also, as you increase the temperature of materials, their resistivities will decrease.

Ans. As the temperature increases more electrons will get the energy to jump from the conduction band to the valence band, and hence increases the conductivity of the semiconductor. So as the temperature gets higher, the resistivity of semiconductors decreases.

Ans. When the temperature increases the gap between the bands becomes very less and the electrons move from the valence band to the conduction band. Thus when the temperature increases in a semiconductor, the density of the charged electrons also increases, and the resistivity decreases.

Ans. When the temperature increases, covalent bonds between compounds break down due to thermal energy supplied to semiconductors. Hence electrons become free, which are engaged in the formation of bonds. Hence, a high-temperature semiconductor no longer behaves as an insulator.

Ans. The resistivity of materials depends on the material’s atomic structure. So we can change the resistivity of a substance by changing the temperature. We also know that the valence electrons are loosely held in the nucleus.

Ans. As R = pl/A, therefore, A = pl/R

For both wires, R and l are the same, and ρ copper < p manganis.

∴ A copper < A manganin

So we can say that Manganin wire is thicker than copper wire.

Ans. When we stretch the wire the resistance of the wire will get to four times, i.e., 80 Ω as volume is constant and R α l₂

So the two equal parts will have a resistance of 40 Ω each.

When connected in parallel, the equivalent resistance will be 20 Ω

Therefore, the current drawn will be given by = V/R_eq

So, it will be equal to = 4/20 = 0.2A.

Ans. The difference between Resistivity and Resistance is: 

Ans. If the temperature of a metallic conductor which is connected to the circuit increases, its resistance also increases.

Thus, factors on which resistance of a conductor depends are:

1. its length,
2. its area of cross-section,
3. the nature of its material and
4. its temperature.

Ans. Resistivity ( ρ ) depends on the mass of the charge carrier (m), and relaxation time ( τ ). Length and mass cannot be a function of T as the mass of a body are constant everywhere. So discards answer (d) and length of body changes negligibly with temperature discards answer (c). 

As τ decreases on increasing T due to the rise in the speed of change-carriers and n increases on increasing temperature. So will affect the ρ or ρ is the function of T verifies answers (a) and (b)

Ans. The resistance of a conductor is given by the relation: R  = V/I 

Given: V = 20V 

I = 20mA = 0.02 A 

Plugging in the values inside the relation, 

R = V/I 

⇒ R = (20)/(0.02) 

⇒ R= 1000 Ohms

Ans. The resistance of a conductor is given by: R = \(\frac{\rho l}{A}\)

Given:

l = 0.1m 

A = 0.01 m2

ρ = 1 x 10-8 

Plugging the values in the relation given above,

 R =\( \frac{\rho l}{A}\)

⇒ R =\( \frac{1 \times 10^{-8} 0.1}{0.01}\)

⇒ R = 10-7

Ans. The resistivity of metallic conductors is given by the following equation: 

ρT = ρ0[ 1 + a(T – T0)]

Here, 

ρT =?

ρ0 = 15.4 nOhm-n 

a = 0.0045 

ρT = ρ0[ 1 + a(T – T0)]

⇒ ρT = 15.4[ 1 + (0.0045)(50)]

⇒ ρT = 15.4[1.225] 

⇒ ρT = 18.86

Ans. Resistance of a conductor denotes the conductor’s opposition to the charge flow through all of it. Two parts of an electric field are set when a potential difference is introduced across a conductor.

Metal has various electrons and an equivalent number of positive ions that don’t move in the presence of free electron movement. This leads to the acceleration of electrons. The ions and atoms collide as the electrons pass, thus their motion is in opposition. Conductor resistance is the antagonism supplied by ions and atoms.

Ans. Property of a material that hinders the flow of electrons is called resistance. Temperature, the area of the cross-section of the wire, which is inversely proportional, and the type of material used are the elements that affect resistance and determine the flow of power. The resistance is mostly unaffected by the conductor’s overall form. Thus, choosing the right material will aid in the proper resistance or conductivity.

Ans. At T = 27^oC, R = 100Ω

R1 ​= 117Ω

Thermal coefficient, α = R(T1​−T) R1 ​− R ​= 1.70 × 10 − 4C − 1

⇒ T1 ​= 1027°C

Ans. Electrical resistivity can be defined as the basic property of a body which helps in the measurement of the extent to which the body resists the movement of electric current. In simple words, the lower the resistivity, the better will be the current flow.

Ans. Resistivity is basically indirectly proportional to the temperature. With increase in the material’s temperature, the resistivities decrease. However, this isn’t true for every material. In other words, not all materials have the same dependence on temperature.

Ans. Electrical resistivity can be denoted by ρ (rho).

Ans. Resistivity can be expressed as the reciprocal of conductivity. With higher conductivity, the resistivity of the material will be lower and vice versa.