What is the temperature co-efficient of resistance?

What is the temperature co-efficient of resistance?
by

1 Answer

Answer :

Temperature co-efficient of the resistance of any substance is, change in its original resistance due to the change in temperature. The temperature co-efficient of resistance of material is the ratio of increase in resistance of 1°C rise in temperature to the original resistance of the material (strictly at 0°C). Formula for the resistance measurement is,

image

by

Related questions

The transducer with negative temperature co-efficient of resistance is

Description : The transducer with negative temperature co-efficient of resistance is (A) Thermistor (B) Resistance Thermometer (C) Strain Gauge (D) Thermocouple

Last Answer : The transducer with negative temperature co-efficient of resistance is Thermistor

______ has zero temperature co-efficient of resistance.

Description :  ______ has zero temperature co-efficient of resistance.

Last Answer :  Manganin has zero temperature co-efficient of resistance.

Temperature co-efficient of resistance is expressed in terms of?

Description : Temperature co-efficient of resistance is expressed in terms of?

Last Answer : Degree celsius

Brass tubes are used in the manufacture of tubes of evaporators used in sugar and salt industries, mainly because of its (A) High co-efficient of thermal expansion (B) Low thermal conductivity (C) High corrosion resistance (D) All (A), (B) and (C)

Description : Brass tubes are used in the manufacture of tubes of evaporators used in sugar and salt industries, mainly because of its (A) High co-efficient of thermal expansion (B) Low thermal conductivity (C) High corrosion resistance (D) All (A), (B) and (C)

Last Answer : (C) High corrosion resistance

Controlling heat transfer film co-efficient is the one, which offers __________ resistance to heat transfer. (A) No (B) The least (C) The largest (D) Lower

Description : Controlling heat transfer film co-efficient is the one, which offers __________ resistance to heat transfer. (A) No (B) The least (C) The largest (D) Lower

Last Answer : (C) The largest

If h1 = inner film co-efficient and /h2 = outer film co-efficient, then the overall heat transfer co-efficient is (A) Always less than h1 (B) Always between h1 and h2 (C) Always higher than h2 (D) Dependent on metal resistance

Description : If h1 = inner film co-efficient and /h2 = outer film co-efficient, then the overall heat transfer co-efficient is (A) Always less than h1 (B) Always between h1 and h2 (C) Always higher than h2 (D) Dependent on metal resistance

Last Answer : (B) Always between h1 and h2

Presence of a non-condensing gas in a condensing vapour (A) Increases the rate of condensation (B) Decreases thermal resistance (C) Is desirable to increase the film co-efficient (D) None of these

Description : Presence of a non-condensing gas in a condensing vapour (A) Increases the rate of condensation (B) Decreases thermal resistance (C) Is desirable to increase the film co-efficient (D) None of these

Last Answer : (D) None of these

In case of hydraulically smooth pipe, the resistance to flow depends only on the Reynolds number, whereas for a hydraulically rough pipe, the resistance to flow is governed by the relative roughness. Two pipes are said to have the same hydraulic roughness, when they have equal values of (A) Relative roughness (B) Absolute roughness (C) Friction co-efficient for flows at equal Reynold number (D) All (A), (B) & (C)

Description : In case of hydraulically smooth pipe, the resistance to flow depends only on the Reynolds number, whereas for a hydraulically rough pipe, the resistance to flow is governed by the relative roughness. Two pipes are said ... co-efficient for flows at equal Reynold number (D) All (A), (B) & (C)

Last Answer : (C) Friction co-efficient for flows at equal Reynold number

Superior quality laboratory apparatus is made of the __________ glass having low thermal co-efficient of expansion & high chemical resistance. (A) Flint (B) Soda (C) Pyrex (D) Potash

Description : Superior quality laboratory apparatus is made of the __________ glass having low thermal co-efficient of expansion & high chemical resistance. (A) Flint (B) Soda (C) Pyrex (D) Potash

Last Answer : (C) Pyrex

Co-efficient of wind resistance of a circular surface, is (A) 1/2 (B) 1/3 (C) 2/3 (D) 3/2

Description : Co-efficient of wind resistance of a circular surface, is  (A) 1/2  (B) 1/3  (C) 2/3  (D) 3/2

Last Answer : (C) 2/3

For calculating the tractive force along an upgrade of an asphalt road, the most probable value of the co-efficient of traction resistance is assumed (A) 1/10 (B) 1/20 (C) 1/30 (D) 1/100

Description : For calculating the tractive force along an upgrade of an asphalt road, the most probable value of the co-efficient of traction resistance is assumed (A) 1/10 (B) 1/20 (C) 1/30 (D) 1/100

Last Answer : Answer: Option D

For aluminium, as compared to copper, all the following factors have higher values except (a) specific volume (6) electrical conductivity (c) co-efficient of linear expansion (d) resistance per unit length for same cross-section

Description : For aluminium, as compared to copper, all the following factors have higher values except (a) specific volume (6) electrical conductivity (c) co-efficient of linear expansion (d) resistance per unit length for same cross-section

Last Answer : (6) electrical conductivity

An ideal coolant for a nuclear reactor should (A) Be a good absorber of neutrons (B) Be capable of attaining high temperature, only when it is pressurised (C) Have high density, but low heat transfer co-efficient (D) Be free from radiation damage and non-corrosive

Description : An ideal coolant for a nuclear reactor should (A) Be a good absorber of neutrons (B) Be capable of attaining high temperature, only when it is pressurised (C) Have high density, but low heat transfer co-efficient (D) Be free from radiation damage and non-corrosive

Last Answer : (D) Be free from radiation damage and non-corrosive

Gaseous diffusion co-efficient increases with increase in the (A) Pressure (B) Temperature (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Gaseous diffusion co-efficient increases with increase in the (A) Pressure (B) Temperature (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (B) Temperature

Mass transfer co-efficient of liquid is (A) Affected more by temperature than that for gases (B) Affected much less by temperature than that for gases

Description : Mass transfer co-efficient of liquid is (A) Affected more by temperature than that for gases (B) Affected much less by temperature than that for gases

Last Answer : (A) Affected more by temperature than that for gases

Diffusion co-efficient generally depends upon the temperature, pressure & the nature of the components of the system. Its dimension is not the same as that of the (A) Mass transfer co-efficient (B) Thermal diffusivity (C) Kinematic viscosity (D) Volumetric diffusivity

Description : Diffusion co-efficient generally depends upon the temperature, pressure & the nature of the components of the system. Its dimension is not the same as that of the (A) Mass transfer co-efficient (B) Thermal diffusivity (C) Kinematic viscosity (D) Volumetric diffusivity

Last Answer : (A) Mass transfer co-efficient

Pick out the wrong statement. (A) In solvent extraction, the distribution co-efficient should be as large as possible for solvent economy (B) With increase in pressure, the solubility of gases in solvent increases at a fixed temperature (C) Decrease in Murphree plate efficiency is an indication of entrainment in distillation column (D) The capacity of a distillation column is maximum at total reflux

Description : Pick out the wrong statement. (A) In solvent extraction, the distribution co-efficient should be as large as possible for solvent economy (B) With increase in pressure, the solubility of ... in distillation column (D) The capacity of a distillation column is maximum at total reflux

Last Answer : (D) The capacity of a distillation column is maximum at total reflux

Condensing film co-efficient for steam on horizontal tubes ranges from 5000 to 15000 Kcal/hr.m2 .°C. Condensation of vapor is carried out inside the tube in a shell and tube heat exchanger, when the (A) Higher condensing film co-efficient is desired (B) Condensate is corrosive in nature (C) Lower pressure drop through the exchanger is desired (D) Temperature of the incoming vapor is very high Answer: Option B

Description : Condensing film co-efficient for steam on horizontal tubes ranges from 5000 to 15000 Kcal/hr.m2 .°C. Condensation of vapor is carried out inside the tube in a shell and tube heat ... drop through the exchanger is desired (D) Temperature of the incoming vapor is very high

Last Answer : (B) Supersaturated

As the difference between the wall temperature and bulk temperature increases, the boiling heat transfer co-efficient (A) Continues to increase (B) Continues to decrease (C) Goes through a minimum (D) Goes through a maximum

Description : As the difference between the wall temperature and bulk temperature increases, the boiling heat transfer co-efficient (A) Continues to increase (B) Continues to decrease (C) Goes through a minimum (D) Goes through a maximum

Last Answer : (C) Goes through a minimum

Log mean temperature difference (LMTD) cannot be used, if (A) Heat transfer co-efficient over the entire heat exchanger is not constant (B) There exists an unsteady state (C) The heat capacity is not constant and there is a phase change (D) None of these

Description : Log mean temperature difference (LMTD) cannot be used, if (A) Heat transfer co-efficient over the entire heat exchanger is not constant (B) There exists an unsteady state (C) The heat capacity is not constant and there is a phase change (D) None of these

Last Answer : (D) None of these

Heat transfer co-efficient (h1 ) for liquids increases with (A) Increasing temperature (B) Decreasing temperature (C) Decreasing Reynolds number (D) None of these

Description : Heat transfer co-efficient (h1 ) for liquids increases with (A) Increasing temperature (B) Decreasing temperature (C) Decreasing Reynolds number (D) None of these

Last Answer : (A) Increasing temperature

Increasing the liquor level in the evaporator results in the (A) Decreased capacity (B) Increase in liquor film co-efficient (C) Decreased effect of hydrostatic head (D) Increased true temperature drop

Description : Increasing the liquor level in the evaporator results in the (A) Decreased capacity (B) Increase in liquor film co-efficient (C) Decreased effect of hydrostatic head (D) Increased true temperature drop

Last Answer : (A) Decreased capacity

The left face of a one dimensional slab of thickness 0.2 m is maintained at 80°C and the right face is exposed to air at 30°C. The thermal conductivity of the slab is 1.2 W/m.K and the heat transfer co-efficient from the right face is 10 W/m2 .K. At steady state, the temperature of the right face in °C is (A) 77.2 (B) 71.2 (C) 63.8 (D) 48.7

Description : The left face of a one dimensional slab of thickness 0.2 m is maintained at 80°C and the right face is exposed to air at 30°C. The thermal conductivity of the slab is 1.2 W/m.K and the heat transfer co-efficient from the ... temperature of the right face in °C is (A) 77.2 (B) 71.2 (C) 63.8 (D) 48.7

Last Answer : (D) 48.7

The main purpose of providing fins on heat transfer surface is to increase the (A) Temperature gradient (B) Mechanical strength of the equipment (C) Heat transfer area (D) Heat transfer co-efficient

Description : The main purpose of providing fins on heat transfer surface is to increase the (A) Temperature gradient (B) Mechanical strength of the equipment (C) Heat transfer area (D) Heat transfer co-efficient

Last Answer : (C) Heat transfer area

It is not preferable to use superheated steam in evaporators, because of its very (A) High temperature (B) High pressure (C) Low film co-efficient (D) None of these

Description : It is not preferable to use superheated steam in evaporators, because of its very (A) High temperature (B) High pressure (C) Low film co-efficient (D) None of these

Last Answer : (C) Low film co-efficient

. The inner wall of a furnace is at a temperature of 700°C. The composite wall is made of two substances, 10 and 20 cm thick with thermal conductivities of 0.05 and 0.1 W.m-1.°C-1 respectively. The ambient air is at 30°C and the heat transfer co-efficient between the outer surface of wall and air is 20 W.m-2 .°C-1 . The rate of heat loss from the outer surface in W.m-2 is (A) 165.4 (B) 167.5 (C) 172.5 (D) 175

Description : . The inner wall of a furnace is at a temperature of 700°C. The composite wall is made of two substances, 10 and 20 cm thick with thermal conductivities of 0.05 and 0.1 W.m-1.°C-1 respectively. The ambient air is at 30°C ... from the outer surface in W.m-2 is (A) 165.4 (B) 167.5 (C) 172.5 (D) 175

Last Answer : (A) 165.4

In a shell and tube heat exchanger, floating head is used for (A) Large temperature differentials (B) High heat transfer co-efficient (C) Low pressure drop (D) Less corrosion of tubes

Description : In a shell and tube heat exchanger, floating head is used for (A) Large temperature differentials (B) High heat transfer co-efficient (C) Low pressure drop (D) Less corrosion of tubes

Last Answer : (A) Large temperature differentials

The film co-efficient between condensing vapour and metal wall increases with (A) Increasing temperature of the vapour (B) Decreasing temperature of the vapour (C) Increasing viscosity of the film of condensate (D) Increasing temperature drop

Description : The film co-efficient between condensing vapour and metal wall increases with (A) Increasing temperature of the vapour (B) Decreasing temperature of the vapour (C) Increasing viscosity of the film of condensate (D) Increasing temperature drop

Last Answer : (A) Increasing temperature of the vapour

Walls of a cubical oven are of thickness l, and they are made of material of thermal conductivity k. The temperature inside the oven is 100°C and the inside heat transfer co-efficient is ‘3k/l’. If the wall temperature on the outside is held at 25°C, what is the inside wall temperature in degree centigrade?(A) 35.5 (B) 43.75 (C) 81.25 (D) 48.25

Description : Walls of a cubical oven are of thickness l, and they are made of material of thermal conductivity k. The temperature inside the oven is 100°C and the inside heat transfer co-efficient is 3k/l'. If the wall temperature ... wall temperature in degree centigrade? (A) 35.5 (B) 43.75 (C) 81.25 (D) 48.25

Last Answer : (C) 81.25

Sudden temperature fluctuation does not affect pyrex glass, because of its (A) Low co-efficient of expansion (B) High co-efficient of expansion (C) High melting point (D) Both (B) and (C)

Description : Sudden temperature fluctuation does not affect pyrex glass, because of its (A) Low co-efficient of expansion (B) High co-efficient of expansion (C) High melting point (D) Both (B) and (C)

Last Answer : (A) Low co-efficient of expansion

Co-efficient of Performance (COP) of a refrigerator is the ratio of the (A) Work required to refrigeration obtained (B) Refrigeration obtained to the work required (C) Lower to higher temperature (D) Higher to lower temperature

Description : Co-efficient of Performance (COP) of a refrigerator is the ratio of the (A) Work required to refrigeration obtained (B) Refrigeration obtained to the work required (C) Lower to higher temperature (D) Higher to lower temperature

Last Answer : (B) Refrigeration obtained to the work required

Free energy, fugacity and activity co-efficient are all affected by change in the temperature. The fugacity co-efficient of a gas at constant pressure ____with the increase of reduced temperature. (A) Decreases (B) Increases (C) Remains constant

Description : Free energy, fugacity and activity co-efficient are all affected by change in the temperature. The fugacity co-efficient of a gas at constant pressure ____with the increase of reduced temperature. (A) Decreases (B) Increases (C) Remains constant

Last Answer : (B) Increases

The co-efficient of performance (COP) of a refrigerating system, which is its index of performance, is defined as the ratio of useful refrigeration to the net work. The units of __________ and COP are the same. (A) Kinematic viscosity (B) Work (C) Temperature (D) None of these

Description : The co-efficient of performance (COP) of a refrigerating system, which is its index of performance, is defined as the ratio of useful refrigeration to the net work. The units of __________ and COP are the same. (A) Kinematic viscosity (B) Work (C) Temperature (D) None of these

Last Answer : (D) None of these

Joule-Thomson co-efficient depends on the (A) Pressure (B) Temperature (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Joule-Thomson co-efficient depends on the (A) Pressure (B) Temperature (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

In a homogeneous solution, the activity co-efficient of a component depends upon the (A) Pressure (B) Composition (C) Temperature (D) All (A), (B) and (C)

Description : In a homogeneous solution, the activity co-efficient of a component depends upon the (A) Pressure (B) Composition (C) Temperature (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Which of the following is not affected by temperature changes? (A) Fugacity (B) Activity co-efficient (C) Free energy (D) None of these

Description : Which of the following is not affected by temperature changes? (A) Fugacity (B) Activity co-efficient (C) Free energy (D) None of these

Last Answer : (D) None of these

Joule-Thomson co-efficient which is defined as, η = (∂T/∂P)H = 1/Cp (∂H/∂T)P, changes sign at a temperature known as inversion temperature. The value of Joule-Thomson co-efficient at inversion temperature is (A) 0 (B) ∞ (C) +ve (D) -ve

Description : Joule-Thomson co-efficient which is defined as, η = (∂T/∂P)H = 1/Cp (∂H/∂T)P, changes sign at a temperature known as inversion temperature. The value of Joule-Thomson co-efficient at inversion temperature is (A) 0 (B) ∞ (C) +ve (D) -ve

Last Answer : (A) 0

With increase in reduced temperature, the fugacity co-efficient of a gas at constant reduced pressure (A) Increases (B) Decreases (C) Remain same (D) Decreases linearly

Description : With increase in reduced temperature, the fugacity co-efficient of a gas at constant reduced pressure (A) Increases (B) Decreases (C) Remain same (D) Decreases linearly

Last Answer : (A) Increases

A reasonably general expression for vapour-liquid phase equilibrium at low to moderate pressure is φi yi P = Yi xifi° where, Φ is a vapor fugacity component, Yiis the liquid activity co-efficient and fi° is the fugacity of the pure component i. the Ki value (Yi = Ki xi) is therefore, in general a function of (A) Temperature only (B) Temperature and pressure only (C) Temperature, pressure and liquid composition xi only (D) Temperature, pressure, liquid composition xi and vapour composition yi

Description : A reasonably general expression for vapour-liquid phase equilibrium at low to moderate pressure is φi yi P = Yi xifi° where, Φ is a vapor fugacity component, Yiis the liquid activity co- ... and liquid composition xi only (D) Temperature, pressure, liquid composition xi and vapour composition yi

Last Answer : (C) Temperature, pressure and liquid composition xi only

Gibbs-Duhem equation relates composition in liquid phase and the __________ at constant temperature & pressure. (A) Fugacity (B) Partial pressure (C) Activity co-efficient (D) All (A), (B), and (C)

Description : Gibbs-Duhem equation relates composition in liquid phase and the __________ at constant temperature & pressure. (A) Fugacity (B) Partial pressure (C) Activity co-efficient (D) All (A), (B), and (C)

Last Answer : (D) All (A), (B), and (C)

Which one is true for a throttling process? (A) A gas may have more than one inversion temperatures (B) The inversion temperature is different for different gases (C) The inversion temperature is same for all gases (D) The inversion temperature is the temperature at which Joule-Thomson co-efficient is infinity

Description : Which one is true for a throttling process? (A) A gas may have more than one inversion temperatures (B) The inversion temperature is different for different gases (C) The inversion ... gases (D) The inversion temperature is the temperature at which Joule-Thomson co-efficient is infinity

Last Answer : (B) The inversion temperature is different for different gases

Which of the following is affected by the temperature? (A) Fugacity (B) Activity co-efficient (C) Free energy (D) All (A), (B) & (C)

Description : Which of the following is affected by the temperature? (A) Fugacity (B) Activity co-efficient (C) Free energy (D) All (A), (B) & (C)

Last Answer : (D) All (A), (B) & (C)

Joule-Thomson co-efficient is the ratio of (A) Pressure change to temperature change occuring during adiabatic compression of a gas (B) Pressure change to temperature change occuring during adiabatic throttling of a gas (C) Temperature change to pressure change occuring during adiabatic compression of a gas (D) Temperature change to pressure change occuring during adiabatic throttling of a gas

Description : Joule-Thomson co-efficient is the ratio of (A) Pressure change to temperature change occuring during adiabatic compression of a gas (B) Pressure change to temperature change occuring during adiabatic ... a gas (D) Temperature change to pressure change occuring during adiabatic throttling of a gas

Last Answer : (D) Temperature change to pressure change occuring during adiabatic throttling of a gas

A thin, flat & square plate measuring 2 m × 2 m is freely hanging in ambient air at 25°C. It is exposed to the solar radiation falling on one side of the plate at the rate of 500 W/m2. The plate temperature will remain constant at 30°C, if the convective heat transfer co-efficient is __________ W/m2 °C. (A) 50 (B) 100 (C) 150 (D) 200

Description : A thin, flat & square plate measuring 2 m 2 m is freely hanging in ambient air at 25°C. It is exposed to the solar radiation falling on one side of the plate at the rate of 500 W/m2. The plate temperature will ... heat transfer co-efficient is __________ W/m2 °C. (A) 50 (B) 100 (C) 150 (D) 200

Last Answer : (B) 100

Diffusion co-efficient of a metal in a solid solution depends upon its (A) Composition (B) Temperature (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Diffusion co-efficient of a metal in a solid solution depends upon its (A) Composition (B) Temperature (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

A block of weight 20 kg slides with an initial velocity of 2 m sec down an inclined plane on to a spring of stiffness 10 kg/cm. If the co--efficient of friction is 0.2, angle ? = 30 the ratio of maximum compession of spring, neglecting friction to that while considering friction would be a.More than one b.One c.Less than one d.Depends on the stiffness of spring e.None of the above

Description : A block of weight 20 kg slides with an initial velocity of 2 m sec down an inclined plane on to a spring of stiffness 10 kg/cm. If the co--efficient of friction is 0.2, angle ? = 30 the ratio of ... be a.More than one b.One c.Less than one d.Depends on the stiffness of spring e.None of the above

Last Answer : a. More than one

A particle moves along a rough plane inclined at 30? to the horizontal. The co-efficient of friction between the particle and the plane is 0.1. Its initial velocity is 15 m/sec. The ratio of the velocity of the particle when it move down the plane to that when it move up the plane would be in the regions a.8 ? 10 b.5 ? 7 c.2 ? 3 d.4 ? 6 e.10 ? 13

Description : A particle moves along a rough plane inclined at 30? to the horizontal. The co-efficient of friction between the particle and the plane is 0.1. Its initial velocity is 15 m/sec. The ratio of the velocity of the particle when it move ... be in the regions a.8 ? 10 b.5 ? 7 c.2 ? 3 d.4 ? 6 e.10 ? 13

Last Answer : b. 5 ? 7

Which one of the following is a nondimensional quantity? (1) Gas constant (2) Strain (3) Co-efficient of viscosity (4) Plank's constant

Description : Which one of the following is a nondimensional quantity? (1) Gas constant (2) Strain (3) Co-efficient of viscosity (4) Plank's constant

Last Answer : (2) Strain Explanation: A dimensionless quantity is simply a quantity that has no units and therefore no dimensions. A ratio between two numbers is a non-dimensional or dimensionless quantity. ... in dimension over original dimension has no dimensional formula. So it is a. dimensionless quantity.