Thermal Properties - Properties and Applications of Materials - Engineering Sciences Previous Year Questions

1

2008 · Engineering Sciences · Properties and Applications of Materials · Thermal Properties

Engineering Sciences (XE) 2008

At constant volume, the energy required to raise the temperature of 1 g of a monatomic solid (atomic mass: 24 amu) by 1°C at T >> θDebye is

A

0.20 cal

B

0.25 cal

C

0.30 cal

D

0.35 cal

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2

2008 · Engineering Sciences · Properties and Applications of Materials · Thermal Properties

Engineering Sciences (XE) 2008

The heat flow across the thickness to the opposite surface of a plastic slab of dimensions 0.1m x 0.1m x 0.05m is 19W. If the temperature difference between the surface of the slab is 10K, the thermal conductivity of the material will be

A

0.3 WK^-1m^-1

B

35.1 WK^-1m^-1

C

2.1 WK^-1m^-1

D

9.5 WK^-1m^-1

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3

2009 · Engineering Sciences · Properties and Applications of Materials · Thermal Properties

Engineering Sciences (XE) 2009

Thermal conductivity of a material at a temperature greater than Debye temperature

A

is independent of temperature

B

decreases inversely with temperature

C

increases linearly with temperature

D

increases exponentially with temperature

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4

2011 · Engineering Sciences · Properties and Applications of Materials · Thermal Properties

Engineering Sciences (XE) 2011

Which one of the following materials has the lowest coefficient of thermal expansion?

A

Superalloy

B

Super Invar

C

Spinel

D

α-brass

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5

2011 · Engineering Sciences · Properties and Applications of Materials · Thermal Properties

Engineering Sciences (XE) 2011

Match the properties in Column-I with the appropriate units in Column-II

Column-I
P. Thermal conductivity
Q. Dielectric strength
R. Magnetic permeability
S. Capacitance

Column-II
1. H m^-1
2. Wb m^-2
3. W m^-1 K^-1
4. V m^-1
5. C V^-1
6. J mol^-1 K^-1

A

P-6, Q-4, R-2, S-5

B

P-3, Q-5, R-1, S-4

C

P-3, Q-4, R-1, S-5

D

P-6, Q-5, R-1, S-4

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6

2012 · Engineering Sciences · Properties and Applications of Materials · Thermal Properties

Engineering Sciences (XE) 2012

Which material has the lowest specific heat capacity at room temperature?

A

Water

B

Mercury

C

Copper

D

Silver

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7

2012 · Engineering Sciences · Properties and Applications of Materials · Thermal Properties

Engineering Sciences (XE) 2012

The crystalline melting temperature of the polymers high density polyethylene (HDPE), isotactic polypropylene (iPP), nylon 6 (PA6) and poly(ethylene terephthalate) (PET) can be arranged as

A

T_HDPE > T_PET > T_iPP > T_PA6

B

T_PET > T_PA6 > T_iPP > T_HDPE

C

T_PA6 > T_HDPE > T_PET > T_iPP

D

T_iPP > T_PA6 > T_PET > T_HDPE

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8

2012 · Engineering Sciences · Properties and Applications of Materials · Thermal Properties

Engineering Sciences (XE) 2012

Most engineering polymers have heat distortion temperature (HDT) in excess of

A

-80°C

B

0°C

C

20°C

D

80°C

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9

2013 · Engineering Sciences · Properties and Applications of Materials · Thermal Properties

Engineering Sciences (XE) 2013

For automatic control of household electric water heater a relay switch is activated by thermal expansion of a brass rod of length 50 cm as shown in the schematic below. The distance between the rod and the lever, x, is adjusted by moving the base of the rod. As the water gets heated the rod expands and as soon as the rod touches the lever, the circuit is broken disconnecting the heater from the power supply. Find the distance, x, in mm, to be set at water temperature of 20°C such that the circuit is broken at 70°C. The coefficient of linear thermal expansion of brass is 20 x 10⁻⁶°C⁻¹

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10

2013 · Engineering Sciences · Properties and Applications of Materials · Thermal Properties

Engineering Sciences (XE) 2013

The length of a glass fiber reinforced polymer increased by 0.03mm, from its initial length of 100mm, when the temperature was changed from -30°C to +30°C. The coefficient of linear thermal expansion is

A

1.03 x 10^-3 °C^-1

B

9.82 x 10^-6 °C^-1

C

5.00 x 10^-6 °C^-1

D

14.4 x 10^-5 °C^-1

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11

2015 · Engineering Sciences · Properties and Applications of Materials · Thermal Properties

Engineering Sciences (XE) 2015

Arrange the following elements in order of increasing melting point:
(P) gallium (Q) tungsten (R) aluminium (S) gold

A

P < R < Q < S

B

S < P < R < Q

C

P < R < S < Q

D

R < S < Q < P

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12

2015 · Engineering Sciences · Properties and Applications of Materials · Thermal Properties

Engineering Sciences (XE) 2015

Which of the following statements is TRUE about the glass transition temperature (T_g)?

A

T_g appears below the melting temperature in a perfectly crystalline material

B

Upon heating through T_g, heat capacity remains constant but the thermal expansion coefficient changes

C

Upon heating through T_g, heat capacity changes but the thermal expansion coefficient remains the same

D

Upon heating through T_g, both the heat capacity and thermal expansion coefficient change

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13

2015 · Engineering Sciences · Properties and Applications of Materials · Thermal Properties

Engineering Sciences (XE) 2015

With increasing temperature from 15°C in winter to 45°C in summer, the length of an iron rail track increases by 0.05 cm. Calculate the original length of the iron rail track in cm. (linear thermal expansion coefficient of iron is 11.0 x 10⁻⁶ K⁻¹)

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14

2016 · Engineering Sciences · Properties and Applications of Materials · Thermal Properties

Engineering Sciences (XE) 2016

Which one of the following effects is the working principle of a thermocouple?

A

Thomson

B

Seebeck

C

Peltier

D

Meissner

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15

2017 · Engineering Sciences · Properties and Applications of Materials · Thermal Properties

Engineering Sciences (XE) 2017

Length of a certain metal rod at 0 °C is 10 cm. The coefficient of linear expansion of that metal varies with temperature as 10^-4 + 10^-5×T (cm/cm)/°C. When the length of the metal rod is 10.2 cm, the rise in temperature in °C is ________.

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16

2018 · Engineering Sciences · Properties and Applications of Materials · Thermal Properties

Engineering Sciences (XE) 2018

For a two-dimensional solid, the variation of lattice specific heat as a function of temperature \(T\) (in K, at low temperatures) is given as: \(C_p = bT^n\), where \(b\) is a constant. The value of \(n\) is __________.

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17

2021 · Engineering Sciences · Properties and Applications of Materials · Thermal Properties

Engineering Sciences (XE) 2021

At 1000 K, the linear thermal expansion coefficients of graphite, parallel and perpendicular to the graphite layers, are \(0.8 \times 10^{-6} \; \mathrm{K^{-1}}\) and \(29 \times 10^{-6} \; \mathrm{K^{-1}}\), respectively. The percentage increase in the volume of graphite when heated from 900 K to 1100 K is __________ (round off to 2 decimal places)

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18

2022 · Engineering Sciences · Properties and Applications of Materials · Thermal Properties

Engineering Sciences (XE) 2022

The thermal conductivity values of glass fiber and epoxy resin are 1.05 W m⁻¹ K⁻¹ and 0.25 W m⁻¹ K⁻¹, respectively. The thermal conductivity of a glass fiber reinforced epoxy composite with a fiber content of 60% by volume along the fiber direction is __________ W m⁻¹ K⁻¹ (rounded off to two decimal places).

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19

2023 · Engineering Sciences · Properties and Applications of Materials · Thermal Properties

Engineering Sciences (XE) 2023

Specific heat \(C_v\) of a material was found to depend on temperature as shown below. Which of the following statement(s) is/are true?

A

The material is metallic

B

The material is insulating

C

The material is three dimensional

D

The material is one dimensional

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