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Heat Transfer

149459 A body at $3000 K$ emits maximum energy at a wavelength of $9660 \AA$ . If the sum emits maximum energy at a wavelength of $4950 \AA$ . Then what would be the temperature of the sun?

1

5855 K

2

7000 K

3

4250 K

4

8000 K

Explanation:

A Given that,
${(λ_{m})}_{1} = 9660 \AA T_{1} = 3000 K$
${(λ_{m})}_{2} = 4950 \AA T_{2} = ?$
We know Wien's displacement law,
$\begin{array}{r} λ_{m} \propto \frac{1}{T} \\ \frac{λ_{m_{1}}}{λ_{m_{2}}} = \frac{T_{2}}{T_{1}} \\ \frac{9660}{4950} = \frac{T_{2}}{3000} \\ T_{2} = \frac{9660}{4950} \times 3000 \\ T_{2} = 5854.5454 ≃ 5855 K \end{array}$

AP EAMCET (21.09.2020) Shift-II

Heat Transfer

149461 Wien's displacement law states

1

λ_{m} T =

constant

2

\frac{λ_{m}}{T} =

constant

3

\frac{T}{λ_{m}} =

constant

4

λ_{m} + T = constant

Explanation:

A According to Wien's displacement law, the wavelength $(λ_{m})$ corresponding to which the energy emitted by a black body maximum is inversely proportional to its absolute temperature $(T)$ .
$i.e., λ_{m} \propto \frac{1}{T}$
$λ_{m} = \frac{k}{T} [where, k = Wien's constant]$
$λ_{m} \cdot T = k = constant$

AP EAMCET (21.09.2020) Shift-I

Heat Transfer

149465 The radiation emitted by a perfectly black body is proportional to

1 temperature on ideal gas scale

2 fourth root of temperature on ideal gas scale

3 fourth power of temperature on ideal gas scale

4 square of temperature on ideal gas scale

Explanation:

C Stefan's Boltzmann law states that total energy radiated per unit time is directly proportional to the fourth power of its absolute Temperature i.e.
$E \propto T^{4}$
$E = σ T^{4}$
Where $σ$ is the Stefan's constant

BITSAT-2011

Heat Transfer

149467 The wavelength of radiation emitted by a body depends upon

1 the nature of its surface

2 the area of its surface

3 the temperature of its surface

4 All of the above

Explanation:

C According to Wein's displacement law
$λ_{m} T = Constant$
$λ_{m} \propto \frac{1}{T}$
Hence, the wavelength of radiation emitted by a body depends upon the temperature of the surface

BITSAT-2014

Heat Transfer

149459 A body at $3000 K$ emits maximum energy at a wavelength of $9660 \AA$ . If the sum emits maximum energy at a wavelength of $4950 \AA$ . Then what would be the temperature of the sun?

1

5855 K

2

7000 K

3

4250 K

4

8000 K

Explanation:

A Given that,
${(λ_{m})}_{1} = 9660 \AA T_{1} = 3000 K$
${(λ_{m})}_{2} = 4950 \AA T_{2} = ?$
We know Wien's displacement law,
$\begin{array}{r} λ_{m} \propto \frac{1}{T} \\ \frac{λ_{m_{1}}}{λ_{m_{2}}} = \frac{T_{2}}{T_{1}} \\ \frac{9660}{4950} = \frac{T_{2}}{3000} \\ T_{2} = \frac{9660}{4950} \times 3000 \\ T_{2} = 5854.5454 ≃ 5855 K \end{array}$

AP EAMCET (21.09.2020) Shift-II

Heat Transfer

149461 Wien's displacement law states

1

λ_{m} T =

constant

2

\frac{λ_{m}}{T} =

constant

3

\frac{T}{λ_{m}} =

constant

4

λ_{m} + T = constant

Explanation:

A According to Wien's displacement law, the wavelength $(λ_{m})$ corresponding to which the energy emitted by a black body maximum is inversely proportional to its absolute temperature $(T)$ .
$i.e., λ_{m} \propto \frac{1}{T}$
$λ_{m} = \frac{k}{T} [where, k = Wien's constant]$
$λ_{m} \cdot T = k = constant$

AP EAMCET (21.09.2020) Shift-I

Heat Transfer

149465 The radiation emitted by a perfectly black body is proportional to

1 temperature on ideal gas scale

2 fourth root of temperature on ideal gas scale

3 fourth power of temperature on ideal gas scale

4 square of temperature on ideal gas scale

Explanation:

C Stefan's Boltzmann law states that total energy radiated per unit time is directly proportional to the fourth power of its absolute Temperature i.e.
$E \propto T^{4}$
$E = σ T^{4}$
Where $σ$ is the Stefan's constant

BITSAT-2011

Heat Transfer

149467 The wavelength of radiation emitted by a body depends upon

1 the nature of its surface

2 the area of its surface

3 the temperature of its surface

4 All of the above

Explanation:

C According to Wein's displacement law
$λ_{m} T = Constant$
$λ_{m} \propto \frac{1}{T}$
Hence, the wavelength of radiation emitted by a body depends upon the temperature of the surface

BITSAT-2014

Heat Transfer

149459 A body at $3000 K$ emits maximum energy at a wavelength of $9660 \AA$ . If the sum emits maximum energy at a wavelength of $4950 \AA$ . Then what would be the temperature of the sun?

1

5855 K

2

7000 K

3

4250 K

4

8000 K

Explanation:

A Given that,
${(λ_{m})}_{1} = 9660 \AA T_{1} = 3000 K$
${(λ_{m})}_{2} = 4950 \AA T_{2} = ?$
We know Wien's displacement law,
$\begin{array}{r} λ_{m} \propto \frac{1}{T} \\ \frac{λ_{m_{1}}}{λ_{m_{2}}} = \frac{T_{2}}{T_{1}} \\ \frac{9660}{4950} = \frac{T_{2}}{3000} \\ T_{2} = \frac{9660}{4950} \times 3000 \\ T_{2} = 5854.5454 ≃ 5855 K \end{array}$

AP EAMCET (21.09.2020) Shift-II

Heat Transfer

149461 Wien's displacement law states

1

λ_{m} T =

constant

2

\frac{λ_{m}}{T} =

constant

3

\frac{T}{λ_{m}} =

constant

4

λ_{m} + T = constant

Explanation:

A According to Wien's displacement law, the wavelength $(λ_{m})$ corresponding to which the energy emitted by a black body maximum is inversely proportional to its absolute temperature $(T)$ .
$i.e., λ_{m} \propto \frac{1}{T}$
$λ_{m} = \frac{k}{T} [where, k = Wien's constant]$
$λ_{m} \cdot T = k = constant$

AP EAMCET (21.09.2020) Shift-I

Heat Transfer

149465 The radiation emitted by a perfectly black body is proportional to

1 temperature on ideal gas scale

2 fourth root of temperature on ideal gas scale

3 fourth power of temperature on ideal gas scale

4 square of temperature on ideal gas scale

Explanation:

C Stefan's Boltzmann law states that total energy radiated per unit time is directly proportional to the fourth power of its absolute Temperature i.e.
$E \propto T^{4}$
$E = σ T^{4}$
Where $σ$ is the Stefan's constant

BITSAT-2011

Heat Transfer

149467 The wavelength of radiation emitted by a body depends upon

1 the nature of its surface

2 the area of its surface

3 the temperature of its surface

4 All of the above

Explanation:

C According to Wein's displacement law
$λ_{m} T = Constant$
$λ_{m} \propto \frac{1}{T}$
Hence, the wavelength of radiation emitted by a body depends upon the temperature of the surface

BITSAT-2014

Heat Transfer

149459 A body at $3000 K$ emits maximum energy at a wavelength of $9660 \AA$ . If the sum emits maximum energy at a wavelength of $4950 \AA$ . Then what would be the temperature of the sun?

1

5855 K

2

7000 K

3

4250 K

4

8000 K

Explanation:

A Given that,
${(λ_{m})}_{1} = 9660 \AA T_{1} = 3000 K$
${(λ_{m})}_{2} = 4950 \AA T_{2} = ?$
We know Wien's displacement law,
$\begin{array}{r} λ_{m} \propto \frac{1}{T} \\ \frac{λ_{m_{1}}}{λ_{m_{2}}} = \frac{T_{2}}{T_{1}} \\ \frac{9660}{4950} = \frac{T_{2}}{3000} \\ T_{2} = \frac{9660}{4950} \times 3000 \\ T_{2} = 5854.5454 ≃ 5855 K \end{array}$

AP EAMCET (21.09.2020) Shift-II

Heat Transfer

149461 Wien's displacement law states

1

λ_{m} T =

constant

2

\frac{λ_{m}}{T} =

constant

3

\frac{T}{λ_{m}} =

constant

4

λ_{m} + T = constant

Explanation:

A According to Wien's displacement law, the wavelength $(λ_{m})$ corresponding to which the energy emitted by a black body maximum is inversely proportional to its absolute temperature $(T)$ .
$i.e., λ_{m} \propto \frac{1}{T}$
$λ_{m} = \frac{k}{T} [where, k = Wien's constant]$
$λ_{m} \cdot T = k = constant$

AP EAMCET (21.09.2020) Shift-I

Heat Transfer

149465 The radiation emitted by a perfectly black body is proportional to

1 temperature on ideal gas scale

2 fourth root of temperature on ideal gas scale

3 fourth power of temperature on ideal gas scale

4 square of temperature on ideal gas scale

Explanation:

C Stefan's Boltzmann law states that total energy radiated per unit time is directly proportional to the fourth power of its absolute Temperature i.e.
$E \propto T^{4}$
$E = σ T^{4}$
Where $σ$ is the Stefan's constant

BITSAT-2011

Heat Transfer

149467 The wavelength of radiation emitted by a body depends upon

1 the nature of its surface

2 the area of its surface

3 the temperature of its surface

4 All of the above

Explanation:

C According to Wein's displacement law
$λ_{m} T = Constant$
$λ_{m} \propto \frac{1}{T}$
Hence, the wavelength of radiation emitted by a body depends upon the temperature of the surface

BITSAT-2014