QBManager

Thermal Properties of Matter

146498 A slab consists of portions of different materials of same thickness and having the conductivities $K_{1}$ and $K_{2}$ . The equivalent thermal conductivity of the slab is

1

K_{1} + K_{2}

2

\sqrt{K_{1} + K_{2}}

3

\frac{2 K_{1} K_{2}}{K_{1} + K_{2}}

4

\sqrt{\frac{K_{1} K_{2}}{K_{1} + K_{2}}}

Explanation:

C Given that, $t_{1} = t_{2} = t$
$A_{1} = A_{2} = A$

We know that thermal Resistance
$T_{1} R_{1} = \frac{L}{K_{1} A} R_{2} = \frac{L}{K_{2} A} T_{2}$
$Q = \frac{KA (T_{1} - T_{2})}{L}$
Thermal resistance are in series combination
$R = R_{1} + R_{2}$
$= \frac{L}{K_{1} A} + \frac{L}{K_{2} A}$
$\frac{2 L}{K_{eq} A} = \frac{L}{A} [\frac{1}{K_{1}} + \frac{1}{K_{2}}]$
$\frac{2}{K_{eq}} = \frac{K_{1} + K_{2}}{K_{1} K_{2}}$
$K_{eq} = \frac{2 K_{1} K_{2}}{K_{1} + K_{2}}$

JIPMEER-2015

Thermal Properties of Matter

146396 Mercury boils at $367^{\circ} C$ . However, mercury thermometers are made such that they can measure temperature upto $500^{\circ} C$ . This is done by

1 maintaining vacuum above mercury column in the stem of the thermometer

2 filling nitrogen gas at high pressure above the mercury column

3 filling oxygen gas at high pressure above the mercury column

4 filling nitrogen gas at low pressure above the mercury column

Explanation:

B
Exp:
Mercury thermometer can be used to measure the temperature upto $500^{\circ} C$ because in mercury thermometer, the space above the mercury is filled with the nitrogen and nitrogen increases the boiling point of mercury.

AIPMT 2004

Thermal Properties of Matter

146401 The triple point of water is

1

{273.16}^{\circ} C

2

273.16 K

3

{273.16}^{\circ} F

4

0.15 K

Explanation:

B The triple point of substance is the temperature and pressure at which the three phases (gas, liquid and solid) of that substance co-exist in thermodynamic equilibrium.

The triple point of water is $273.16 K$ , or ${0.01}^{\circ} C$ or ${32.02}^{\circ} F$

AP EAMCET (17.09.2020) Shift-II UPCPMT- 2002

Thermal Properties of Matter

146413 If boiling point of water is $95^{\circ} F$ , what will be reduction at celsius scale?

1

7^{0} C

2

65^{\circ} C

3

63^{0} C

4

35^{\circ} C

Explanation:

D $\frac{^{\circ} C - 0}{100 - 0} = \frac{^{\circ} F - 32}{212 - 32}$
$\frac{^{\circ} C}{100} = \frac{95 - 32}{180}$
$^{\circ} C = \frac{5}{9} \times 63 = 35^{\circ} C$

BCECE-2006

Thermal Properties of Matter

146498 A slab consists of portions of different materials of same thickness and having the conductivities $K_{1}$ and $K_{2}$ . The equivalent thermal conductivity of the slab is

1

K_{1} + K_{2}

2

\sqrt{K_{1} + K_{2}}

3

\frac{2 K_{1} K_{2}}{K_{1} + K_{2}}

4

\sqrt{\frac{K_{1} K_{2}}{K_{1} + K_{2}}}

Explanation:

C Given that, $t_{1} = t_{2} = t$
$A_{1} = A_{2} = A$

We know that thermal Resistance
$T_{1} R_{1} = \frac{L}{K_{1} A} R_{2} = \frac{L}{K_{2} A} T_{2}$
$Q = \frac{KA (T_{1} - T_{2})}{L}$
Thermal resistance are in series combination
$R = R_{1} + R_{2}$
$= \frac{L}{K_{1} A} + \frac{L}{K_{2} A}$
$\frac{2 L}{K_{eq} A} = \frac{L}{A} [\frac{1}{K_{1}} + \frac{1}{K_{2}}]$
$\frac{2}{K_{eq}} = \frac{K_{1} + K_{2}}{K_{1} K_{2}}$
$K_{eq} = \frac{2 K_{1} K_{2}}{K_{1} + K_{2}}$

JIPMEER-2015

Thermal Properties of Matter

146396 Mercury boils at $367^{\circ} C$ . However, mercury thermometers are made such that they can measure temperature upto $500^{\circ} C$ . This is done by

1 maintaining vacuum above mercury column in the stem of the thermometer

2 filling nitrogen gas at high pressure above the mercury column

3 filling oxygen gas at high pressure above the mercury column

4 filling nitrogen gas at low pressure above the mercury column

Explanation:

B
Exp:
Mercury thermometer can be used to measure the temperature upto $500^{\circ} C$ because in mercury thermometer, the space above the mercury is filled with the nitrogen and nitrogen increases the boiling point of mercury.

AIPMT 2004

Thermal Properties of Matter

146401 The triple point of water is

1

{273.16}^{\circ} C

2

273.16 K

3

{273.16}^{\circ} F

4

0.15 K

Explanation:

B The triple point of substance is the temperature and pressure at which the three phases (gas, liquid and solid) of that substance co-exist in thermodynamic equilibrium.

The triple point of water is $273.16 K$ , or ${0.01}^{\circ} C$ or ${32.02}^{\circ} F$

AP EAMCET (17.09.2020) Shift-II UPCPMT- 2002

Thermal Properties of Matter

146413 If boiling point of water is $95^{\circ} F$ , what will be reduction at celsius scale?

1

7^{0} C

2

65^{\circ} C

3

63^{0} C

4

35^{\circ} C

Explanation:

D $\frac{^{\circ} C - 0}{100 - 0} = \frac{^{\circ} F - 32}{212 - 32}$
$\frac{^{\circ} C}{100} = \frac{95 - 32}{180}$
$^{\circ} C = \frac{5}{9} \times 63 = 35^{\circ} C$

BCECE-2006

Thermal Properties of Matter

146498 A slab consists of portions of different materials of same thickness and having the conductivities $K_{1}$ and $K_{2}$ . The equivalent thermal conductivity of the slab is

1

K_{1} + K_{2}

2

\sqrt{K_{1} + K_{2}}

3

\frac{2 K_{1} K_{2}}{K_{1} + K_{2}}

4

\sqrt{\frac{K_{1} K_{2}}{K_{1} + K_{2}}}

Explanation:

C Given that, $t_{1} = t_{2} = t$
$A_{1} = A_{2} = A$

We know that thermal Resistance
$T_{1} R_{1} = \frac{L}{K_{1} A} R_{2} = \frac{L}{K_{2} A} T_{2}$
$Q = \frac{KA (T_{1} - T_{2})}{L}$
Thermal resistance are in series combination
$R = R_{1} + R_{2}$
$= \frac{L}{K_{1} A} + \frac{L}{K_{2} A}$
$\frac{2 L}{K_{eq} A} = \frac{L}{A} [\frac{1}{K_{1}} + \frac{1}{K_{2}}]$
$\frac{2}{K_{eq}} = \frac{K_{1} + K_{2}}{K_{1} K_{2}}$
$K_{eq} = \frac{2 K_{1} K_{2}}{K_{1} + K_{2}}$

JIPMEER-2015

Thermal Properties of Matter

146396 Mercury boils at $367^{\circ} C$ . However, mercury thermometers are made such that they can measure temperature upto $500^{\circ} C$ . This is done by

1 maintaining vacuum above mercury column in the stem of the thermometer

2 filling nitrogen gas at high pressure above the mercury column

3 filling oxygen gas at high pressure above the mercury column

4 filling nitrogen gas at low pressure above the mercury column

Explanation:

B
Exp:
Mercury thermometer can be used to measure the temperature upto $500^{\circ} C$ because in mercury thermometer, the space above the mercury is filled with the nitrogen and nitrogen increases the boiling point of mercury.

AIPMT 2004

Thermal Properties of Matter

146401 The triple point of water is

1

{273.16}^{\circ} C

2

273.16 K

3

{273.16}^{\circ} F

4

0.15 K

Explanation:

B The triple point of substance is the temperature and pressure at which the three phases (gas, liquid and solid) of that substance co-exist in thermodynamic equilibrium.

The triple point of water is $273.16 K$ , or ${0.01}^{\circ} C$ or ${32.02}^{\circ} F$

AP EAMCET (17.09.2020) Shift-II UPCPMT- 2002

Thermal Properties of Matter

146413 If boiling point of water is $95^{\circ} F$ , what will be reduction at celsius scale?

1

7^{0} C

2

65^{\circ} C

3

63^{0} C

4

35^{\circ} C

Explanation:

D $\frac{^{\circ} C - 0}{100 - 0} = \frac{^{\circ} F - 32}{212 - 32}$
$\frac{^{\circ} C}{100} = \frac{95 - 32}{180}$
$^{\circ} C = \frac{5}{9} \times 63 = 35^{\circ} C$

BCECE-2006

Thermal Properties of Matter

146498 A slab consists of portions of different materials of same thickness and having the conductivities $K_{1}$ and $K_{2}$ . The equivalent thermal conductivity of the slab is

1

K_{1} + K_{2}

2

\sqrt{K_{1} + K_{2}}

3

\frac{2 K_{1} K_{2}}{K_{1} + K_{2}}

4

\sqrt{\frac{K_{1} K_{2}}{K_{1} + K_{2}}}

Explanation:

C Given that, $t_{1} = t_{2} = t$
$A_{1} = A_{2} = A$

We know that thermal Resistance
$T_{1} R_{1} = \frac{L}{K_{1} A} R_{2} = \frac{L}{K_{2} A} T_{2}$
$Q = \frac{KA (T_{1} - T_{2})}{L}$
Thermal resistance are in series combination
$R = R_{1} + R_{2}$
$= \frac{L}{K_{1} A} + \frac{L}{K_{2} A}$
$\frac{2 L}{K_{eq} A} = \frac{L}{A} [\frac{1}{K_{1}} + \frac{1}{K_{2}}]$
$\frac{2}{K_{eq}} = \frac{K_{1} + K_{2}}{K_{1} K_{2}}$
$K_{eq} = \frac{2 K_{1} K_{2}}{K_{1} + K_{2}}$

JIPMEER-2015

Thermal Properties of Matter

146396 Mercury boils at $367^{\circ} C$ . However, mercury thermometers are made such that they can measure temperature upto $500^{\circ} C$ . This is done by

1 maintaining vacuum above mercury column in the stem of the thermometer

2 filling nitrogen gas at high pressure above the mercury column

3 filling oxygen gas at high pressure above the mercury column

4 filling nitrogen gas at low pressure above the mercury column

Explanation:

B
Exp:
Mercury thermometer can be used to measure the temperature upto $500^{\circ} C$ because in mercury thermometer, the space above the mercury is filled with the nitrogen and nitrogen increases the boiling point of mercury.

AIPMT 2004

Thermal Properties of Matter

146401 The triple point of water is

1

{273.16}^{\circ} C

2

273.16 K

3

{273.16}^{\circ} F

4

0.15 K

Explanation:

B The triple point of substance is the temperature and pressure at which the three phases (gas, liquid and solid) of that substance co-exist in thermodynamic equilibrium.

The triple point of water is $273.16 K$ , or ${0.01}^{\circ} C$ or ${32.02}^{\circ} F$

AP EAMCET (17.09.2020) Shift-II UPCPMT- 2002

Thermal Properties of Matter

146413 If boiling point of water is $95^{\circ} F$ , what will be reduction at celsius scale?

1

7^{0} C

2

65^{\circ} C

3

63^{0} C

4

35^{\circ} C

Explanation:

D $\frac{^{\circ} C - 0}{100 - 0} = \frac{^{\circ} F - 32}{212 - 32}$
$\frac{^{\circ} C}{100} = \frac{95 - 32}{180}$
$^{\circ} C = \frac{5}{9} \times 63 = 35^{\circ} C$

BCECE-2006