172796
Temperature, $\mathrm{In}^{\circ} \mathrm{C}$, at which velocity of sound will be double of its value at $0^{\circ} \mathrm{C}$ is
1 819
2 546
3 1092
4 596
Explanation:
A Let, $\mathrm{T}$ temperature at which velocity of sound double of its value. Temperature $\mathrm{T}_{1}=0^{\circ} \mathrm{C}=273 \mathrm{~K}$, Velocity at $\mathrm{T}_{1}=\mathrm{v}$ Velocity at $\mathrm{T}_{2}=2 \mathrm{v}$ We know that, $\mathrm{v} \propto \sqrt{\mathrm{T}}$ $\frac{\mathrm{v}_{1}}{\mathrm{v}_{2}} =\sqrt{\frac{\mathrm{T}_{1}}{\mathrm{~T}_{2}}}$ $\frac{\mathrm{v}}{2 \mathrm{v}} =\sqrt{\frac{273}{\mathrm{~T}_{2}}}$ $\mathrm{~T}_{2} =1092 \mathrm{~K} .$ $\mathrm{T}_{2} =(1092-273)^{\circ} \mathrm{C}$ $\mathrm{T}_{2} =819^{\circ} \mathrm{C}$
COMEDK 2011
WAVES
172797
The ratio of speed of sound in Hydrogen to that in Oxygen at the same temperature is
1 $1: 4$
2 $4: 1$
3 $1: 1$
4 $16: 1$
Explanation:
B According to kinetic theory of gases the speed of sound in a gas medium, $\mathrm{v}=\sqrt{\frac{\gamma \mathrm{P}}{\rho}}=\sqrt{\frac{\gamma \mathrm{RT}}{\mathrm{M}}}$ At a constant temperature, $\mathrm{v} \propto \sqrt{\frac{1}{\mathrm{M}}}$ $\frac{\mathrm{v}_{\mathrm{H}_{2}}}{\mathrm{v}_{\mathrm{O}_{2}}}=\sqrt{\frac{\mathrm{M}_{\mathrm{O}_{2}}}{\mathrm{M}_{\mathrm{H}_{2}}}}$ $\frac{\mathrm{v}_{\mathrm{H}_{2}}}{\mathrm{v}_{\mathrm{O}_{2}}}=\sqrt{\frac{32}{2}}=\frac{4}{1}$ $\mathrm{v}_{\mathrm{H}_{2}}: \mathrm{v}_{\mathrm{O}_{2}}=4: 1$ Hence, the ratio of speed of sound in hydrogen and oxygen gas will be $4: 1$.
COMEDK 2012
WAVES
172798
A hospital uses an ultrasonic scanner to locate tumors in a tissue. The operating frequency of the scanner is 4.2 MHz. The speed of sound in a tissue is $1.7 \mathrm{~km} \mathrm{~s}^{-1}$. The wavelength of sound in the tissue is
172800
Assertion: The change in air pressure affects the speed of sound. Reason: The speed of sound in gases is proportional to the square of pressure.
1 If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
2 If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
3 If the Assertion is correct but Reason is incorrect.
4 If both the Assertion and Reason are incorrect.
5 If the Assertion is incorrect but the Reason is correct
Explanation:
D Speed of sound is independent of air pressure. Speed of sound in gases is proportional to the square root of pressure. The square root of pressure, $\mathrm{v}=\sqrt{\frac{\gamma \mathrm{P}}{\rho}}$ We know, $\mathrm{PM}=\rho \mathrm{RT}$ $\frac{\mathrm{P}}{\rho}=\frac{\mathrm{RT}}{\mathrm{M}}=\mathrm{constant}$ At constant temperature, if $\rho$ also varies in such a way that the ratio $\mathrm{P} / \rho$ remains constant. Hence, there is no effect of the pressure change on the speed of sound.
AIIMS-2008
WAVES
172801
Assertion: The pitch of wind instruments rises and that of string instruments falls as an orchestra warms up. Reason: When temperature rises, speed of sound increases but speed of wave in a string fixed at both ends decreases.
1 If both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
2 If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.
3 If Assertion is correct but Reason is incorrect.
4 If both the Assertion and Reason are incorrect.
Explanation:
A For wind instruments:- velocity is directly propertional to square root is temperature $\mathrm{v} \propto \sqrt{\mathrm{T}}$ So, temperature rises velocity also rises for string instruments $\mathrm{v}=\sqrt{\frac{\mathrm{T}}{\mathrm{mL}}} (\text { Where, } \mathrm{T} = \text { tension }$ $\mathrm{m} =\text { string mass }$ $\mathrm{L} =\text { string length }$ As temperature rises tension decreases as string slags So, velocity decreases in this case.
172796
Temperature, $\mathrm{In}^{\circ} \mathrm{C}$, at which velocity of sound will be double of its value at $0^{\circ} \mathrm{C}$ is
1 819
2 546
3 1092
4 596
Explanation:
A Let, $\mathrm{T}$ temperature at which velocity of sound double of its value. Temperature $\mathrm{T}_{1}=0^{\circ} \mathrm{C}=273 \mathrm{~K}$, Velocity at $\mathrm{T}_{1}=\mathrm{v}$ Velocity at $\mathrm{T}_{2}=2 \mathrm{v}$ We know that, $\mathrm{v} \propto \sqrt{\mathrm{T}}$ $\frac{\mathrm{v}_{1}}{\mathrm{v}_{2}} =\sqrt{\frac{\mathrm{T}_{1}}{\mathrm{~T}_{2}}}$ $\frac{\mathrm{v}}{2 \mathrm{v}} =\sqrt{\frac{273}{\mathrm{~T}_{2}}}$ $\mathrm{~T}_{2} =1092 \mathrm{~K} .$ $\mathrm{T}_{2} =(1092-273)^{\circ} \mathrm{C}$ $\mathrm{T}_{2} =819^{\circ} \mathrm{C}$
COMEDK 2011
WAVES
172797
The ratio of speed of sound in Hydrogen to that in Oxygen at the same temperature is
1 $1: 4$
2 $4: 1$
3 $1: 1$
4 $16: 1$
Explanation:
B According to kinetic theory of gases the speed of sound in a gas medium, $\mathrm{v}=\sqrt{\frac{\gamma \mathrm{P}}{\rho}}=\sqrt{\frac{\gamma \mathrm{RT}}{\mathrm{M}}}$ At a constant temperature, $\mathrm{v} \propto \sqrt{\frac{1}{\mathrm{M}}}$ $\frac{\mathrm{v}_{\mathrm{H}_{2}}}{\mathrm{v}_{\mathrm{O}_{2}}}=\sqrt{\frac{\mathrm{M}_{\mathrm{O}_{2}}}{\mathrm{M}_{\mathrm{H}_{2}}}}$ $\frac{\mathrm{v}_{\mathrm{H}_{2}}}{\mathrm{v}_{\mathrm{O}_{2}}}=\sqrt{\frac{32}{2}}=\frac{4}{1}$ $\mathrm{v}_{\mathrm{H}_{2}}: \mathrm{v}_{\mathrm{O}_{2}}=4: 1$ Hence, the ratio of speed of sound in hydrogen and oxygen gas will be $4: 1$.
COMEDK 2012
WAVES
172798
A hospital uses an ultrasonic scanner to locate tumors in a tissue. The operating frequency of the scanner is 4.2 MHz. The speed of sound in a tissue is $1.7 \mathrm{~km} \mathrm{~s}^{-1}$. The wavelength of sound in the tissue is
172800
Assertion: The change in air pressure affects the speed of sound. Reason: The speed of sound in gases is proportional to the square of pressure.
1 If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
2 If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
3 If the Assertion is correct but Reason is incorrect.
4 If both the Assertion and Reason are incorrect.
5 If the Assertion is incorrect but the Reason is correct
Explanation:
D Speed of sound is independent of air pressure. Speed of sound in gases is proportional to the square root of pressure. The square root of pressure, $\mathrm{v}=\sqrt{\frac{\gamma \mathrm{P}}{\rho}}$ We know, $\mathrm{PM}=\rho \mathrm{RT}$ $\frac{\mathrm{P}}{\rho}=\frac{\mathrm{RT}}{\mathrm{M}}=\mathrm{constant}$ At constant temperature, if $\rho$ also varies in such a way that the ratio $\mathrm{P} / \rho$ remains constant. Hence, there is no effect of the pressure change on the speed of sound.
AIIMS-2008
WAVES
172801
Assertion: The pitch of wind instruments rises and that of string instruments falls as an orchestra warms up. Reason: When temperature rises, speed of sound increases but speed of wave in a string fixed at both ends decreases.
1 If both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
2 If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.
3 If Assertion is correct but Reason is incorrect.
4 If both the Assertion and Reason are incorrect.
Explanation:
A For wind instruments:- velocity is directly propertional to square root is temperature $\mathrm{v} \propto \sqrt{\mathrm{T}}$ So, temperature rises velocity also rises for string instruments $\mathrm{v}=\sqrt{\frac{\mathrm{T}}{\mathrm{mL}}} (\text { Where, } \mathrm{T} = \text { tension }$ $\mathrm{m} =\text { string mass }$ $\mathrm{L} =\text { string length }$ As temperature rises tension decreases as string slags So, velocity decreases in this case.
172796
Temperature, $\mathrm{In}^{\circ} \mathrm{C}$, at which velocity of sound will be double of its value at $0^{\circ} \mathrm{C}$ is
1 819
2 546
3 1092
4 596
Explanation:
A Let, $\mathrm{T}$ temperature at which velocity of sound double of its value. Temperature $\mathrm{T}_{1}=0^{\circ} \mathrm{C}=273 \mathrm{~K}$, Velocity at $\mathrm{T}_{1}=\mathrm{v}$ Velocity at $\mathrm{T}_{2}=2 \mathrm{v}$ We know that, $\mathrm{v} \propto \sqrt{\mathrm{T}}$ $\frac{\mathrm{v}_{1}}{\mathrm{v}_{2}} =\sqrt{\frac{\mathrm{T}_{1}}{\mathrm{~T}_{2}}}$ $\frac{\mathrm{v}}{2 \mathrm{v}} =\sqrt{\frac{273}{\mathrm{~T}_{2}}}$ $\mathrm{~T}_{2} =1092 \mathrm{~K} .$ $\mathrm{T}_{2} =(1092-273)^{\circ} \mathrm{C}$ $\mathrm{T}_{2} =819^{\circ} \mathrm{C}$
COMEDK 2011
WAVES
172797
The ratio of speed of sound in Hydrogen to that in Oxygen at the same temperature is
1 $1: 4$
2 $4: 1$
3 $1: 1$
4 $16: 1$
Explanation:
B According to kinetic theory of gases the speed of sound in a gas medium, $\mathrm{v}=\sqrt{\frac{\gamma \mathrm{P}}{\rho}}=\sqrt{\frac{\gamma \mathrm{RT}}{\mathrm{M}}}$ At a constant temperature, $\mathrm{v} \propto \sqrt{\frac{1}{\mathrm{M}}}$ $\frac{\mathrm{v}_{\mathrm{H}_{2}}}{\mathrm{v}_{\mathrm{O}_{2}}}=\sqrt{\frac{\mathrm{M}_{\mathrm{O}_{2}}}{\mathrm{M}_{\mathrm{H}_{2}}}}$ $\frac{\mathrm{v}_{\mathrm{H}_{2}}}{\mathrm{v}_{\mathrm{O}_{2}}}=\sqrt{\frac{32}{2}}=\frac{4}{1}$ $\mathrm{v}_{\mathrm{H}_{2}}: \mathrm{v}_{\mathrm{O}_{2}}=4: 1$ Hence, the ratio of speed of sound in hydrogen and oxygen gas will be $4: 1$.
COMEDK 2012
WAVES
172798
A hospital uses an ultrasonic scanner to locate tumors in a tissue. The operating frequency of the scanner is 4.2 MHz. The speed of sound in a tissue is $1.7 \mathrm{~km} \mathrm{~s}^{-1}$. The wavelength of sound in the tissue is
172800
Assertion: The change in air pressure affects the speed of sound. Reason: The speed of sound in gases is proportional to the square of pressure.
1 If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
2 If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
3 If the Assertion is correct but Reason is incorrect.
4 If both the Assertion and Reason are incorrect.
5 If the Assertion is incorrect but the Reason is correct
Explanation:
D Speed of sound is independent of air pressure. Speed of sound in gases is proportional to the square root of pressure. The square root of pressure, $\mathrm{v}=\sqrt{\frac{\gamma \mathrm{P}}{\rho}}$ We know, $\mathrm{PM}=\rho \mathrm{RT}$ $\frac{\mathrm{P}}{\rho}=\frac{\mathrm{RT}}{\mathrm{M}}=\mathrm{constant}$ At constant temperature, if $\rho$ also varies in such a way that the ratio $\mathrm{P} / \rho$ remains constant. Hence, there is no effect of the pressure change on the speed of sound.
AIIMS-2008
WAVES
172801
Assertion: The pitch of wind instruments rises and that of string instruments falls as an orchestra warms up. Reason: When temperature rises, speed of sound increases but speed of wave in a string fixed at both ends decreases.
1 If both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
2 If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.
3 If Assertion is correct but Reason is incorrect.
4 If both the Assertion and Reason are incorrect.
Explanation:
A For wind instruments:- velocity is directly propertional to square root is temperature $\mathrm{v} \propto \sqrt{\mathrm{T}}$ So, temperature rises velocity also rises for string instruments $\mathrm{v}=\sqrt{\frac{\mathrm{T}}{\mathrm{mL}}} (\text { Where, } \mathrm{T} = \text { tension }$ $\mathrm{m} =\text { string mass }$ $\mathrm{L} =\text { string length }$ As temperature rises tension decreases as string slags So, velocity decreases in this case.
172796
Temperature, $\mathrm{In}^{\circ} \mathrm{C}$, at which velocity of sound will be double of its value at $0^{\circ} \mathrm{C}$ is
1 819
2 546
3 1092
4 596
Explanation:
A Let, $\mathrm{T}$ temperature at which velocity of sound double of its value. Temperature $\mathrm{T}_{1}=0^{\circ} \mathrm{C}=273 \mathrm{~K}$, Velocity at $\mathrm{T}_{1}=\mathrm{v}$ Velocity at $\mathrm{T}_{2}=2 \mathrm{v}$ We know that, $\mathrm{v} \propto \sqrt{\mathrm{T}}$ $\frac{\mathrm{v}_{1}}{\mathrm{v}_{2}} =\sqrt{\frac{\mathrm{T}_{1}}{\mathrm{~T}_{2}}}$ $\frac{\mathrm{v}}{2 \mathrm{v}} =\sqrt{\frac{273}{\mathrm{~T}_{2}}}$ $\mathrm{~T}_{2} =1092 \mathrm{~K} .$ $\mathrm{T}_{2} =(1092-273)^{\circ} \mathrm{C}$ $\mathrm{T}_{2} =819^{\circ} \mathrm{C}$
COMEDK 2011
WAVES
172797
The ratio of speed of sound in Hydrogen to that in Oxygen at the same temperature is
1 $1: 4$
2 $4: 1$
3 $1: 1$
4 $16: 1$
Explanation:
B According to kinetic theory of gases the speed of sound in a gas medium, $\mathrm{v}=\sqrt{\frac{\gamma \mathrm{P}}{\rho}}=\sqrt{\frac{\gamma \mathrm{RT}}{\mathrm{M}}}$ At a constant temperature, $\mathrm{v} \propto \sqrt{\frac{1}{\mathrm{M}}}$ $\frac{\mathrm{v}_{\mathrm{H}_{2}}}{\mathrm{v}_{\mathrm{O}_{2}}}=\sqrt{\frac{\mathrm{M}_{\mathrm{O}_{2}}}{\mathrm{M}_{\mathrm{H}_{2}}}}$ $\frac{\mathrm{v}_{\mathrm{H}_{2}}}{\mathrm{v}_{\mathrm{O}_{2}}}=\sqrt{\frac{32}{2}}=\frac{4}{1}$ $\mathrm{v}_{\mathrm{H}_{2}}: \mathrm{v}_{\mathrm{O}_{2}}=4: 1$ Hence, the ratio of speed of sound in hydrogen and oxygen gas will be $4: 1$.
COMEDK 2012
WAVES
172798
A hospital uses an ultrasonic scanner to locate tumors in a tissue. The operating frequency of the scanner is 4.2 MHz. The speed of sound in a tissue is $1.7 \mathrm{~km} \mathrm{~s}^{-1}$. The wavelength of sound in the tissue is
172800
Assertion: The change in air pressure affects the speed of sound. Reason: The speed of sound in gases is proportional to the square of pressure.
1 If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
2 If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
3 If the Assertion is correct but Reason is incorrect.
4 If both the Assertion and Reason are incorrect.
5 If the Assertion is incorrect but the Reason is correct
Explanation:
D Speed of sound is independent of air pressure. Speed of sound in gases is proportional to the square root of pressure. The square root of pressure, $\mathrm{v}=\sqrt{\frac{\gamma \mathrm{P}}{\rho}}$ We know, $\mathrm{PM}=\rho \mathrm{RT}$ $\frac{\mathrm{P}}{\rho}=\frac{\mathrm{RT}}{\mathrm{M}}=\mathrm{constant}$ At constant temperature, if $\rho$ also varies in such a way that the ratio $\mathrm{P} / \rho$ remains constant. Hence, there is no effect of the pressure change on the speed of sound.
AIIMS-2008
WAVES
172801
Assertion: The pitch of wind instruments rises and that of string instruments falls as an orchestra warms up. Reason: When temperature rises, speed of sound increases but speed of wave in a string fixed at both ends decreases.
1 If both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
2 If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.
3 If Assertion is correct but Reason is incorrect.
4 If both the Assertion and Reason are incorrect.
Explanation:
A For wind instruments:- velocity is directly propertional to square root is temperature $\mathrm{v} \propto \sqrt{\mathrm{T}}$ So, temperature rises velocity also rises for string instruments $\mathrm{v}=\sqrt{\frac{\mathrm{T}}{\mathrm{mL}}} (\text { Where, } \mathrm{T} = \text { tension }$ $\mathrm{m} =\text { string mass }$ $\mathrm{L} =\text { string length }$ As temperature rises tension decreases as string slags So, velocity decreases in this case.
172796
Temperature, $\mathrm{In}^{\circ} \mathrm{C}$, at which velocity of sound will be double of its value at $0^{\circ} \mathrm{C}$ is
1 819
2 546
3 1092
4 596
Explanation:
A Let, $\mathrm{T}$ temperature at which velocity of sound double of its value. Temperature $\mathrm{T}_{1}=0^{\circ} \mathrm{C}=273 \mathrm{~K}$, Velocity at $\mathrm{T}_{1}=\mathrm{v}$ Velocity at $\mathrm{T}_{2}=2 \mathrm{v}$ We know that, $\mathrm{v} \propto \sqrt{\mathrm{T}}$ $\frac{\mathrm{v}_{1}}{\mathrm{v}_{2}} =\sqrt{\frac{\mathrm{T}_{1}}{\mathrm{~T}_{2}}}$ $\frac{\mathrm{v}}{2 \mathrm{v}} =\sqrt{\frac{273}{\mathrm{~T}_{2}}}$ $\mathrm{~T}_{2} =1092 \mathrm{~K} .$ $\mathrm{T}_{2} =(1092-273)^{\circ} \mathrm{C}$ $\mathrm{T}_{2} =819^{\circ} \mathrm{C}$
COMEDK 2011
WAVES
172797
The ratio of speed of sound in Hydrogen to that in Oxygen at the same temperature is
1 $1: 4$
2 $4: 1$
3 $1: 1$
4 $16: 1$
Explanation:
B According to kinetic theory of gases the speed of sound in a gas medium, $\mathrm{v}=\sqrt{\frac{\gamma \mathrm{P}}{\rho}}=\sqrt{\frac{\gamma \mathrm{RT}}{\mathrm{M}}}$ At a constant temperature, $\mathrm{v} \propto \sqrt{\frac{1}{\mathrm{M}}}$ $\frac{\mathrm{v}_{\mathrm{H}_{2}}}{\mathrm{v}_{\mathrm{O}_{2}}}=\sqrt{\frac{\mathrm{M}_{\mathrm{O}_{2}}}{\mathrm{M}_{\mathrm{H}_{2}}}}$ $\frac{\mathrm{v}_{\mathrm{H}_{2}}}{\mathrm{v}_{\mathrm{O}_{2}}}=\sqrt{\frac{32}{2}}=\frac{4}{1}$ $\mathrm{v}_{\mathrm{H}_{2}}: \mathrm{v}_{\mathrm{O}_{2}}=4: 1$ Hence, the ratio of speed of sound in hydrogen and oxygen gas will be $4: 1$.
COMEDK 2012
WAVES
172798
A hospital uses an ultrasonic scanner to locate tumors in a tissue. The operating frequency of the scanner is 4.2 MHz. The speed of sound in a tissue is $1.7 \mathrm{~km} \mathrm{~s}^{-1}$. The wavelength of sound in the tissue is
172800
Assertion: The change in air pressure affects the speed of sound. Reason: The speed of sound in gases is proportional to the square of pressure.
1 If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
2 If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
3 If the Assertion is correct but Reason is incorrect.
4 If both the Assertion and Reason are incorrect.
5 If the Assertion is incorrect but the Reason is correct
Explanation:
D Speed of sound is independent of air pressure. Speed of sound in gases is proportional to the square root of pressure. The square root of pressure, $\mathrm{v}=\sqrt{\frac{\gamma \mathrm{P}}{\rho}}$ We know, $\mathrm{PM}=\rho \mathrm{RT}$ $\frac{\mathrm{P}}{\rho}=\frac{\mathrm{RT}}{\mathrm{M}}=\mathrm{constant}$ At constant temperature, if $\rho$ also varies in such a way that the ratio $\mathrm{P} / \rho$ remains constant. Hence, there is no effect of the pressure change on the speed of sound.
AIIMS-2008
WAVES
172801
Assertion: The pitch of wind instruments rises and that of string instruments falls as an orchestra warms up. Reason: When temperature rises, speed of sound increases but speed of wave in a string fixed at both ends decreases.
1 If both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
2 If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.
3 If Assertion is correct but Reason is incorrect.
4 If both the Assertion and Reason are incorrect.
Explanation:
A For wind instruments:- velocity is directly propertional to square root is temperature $\mathrm{v} \propto \sqrt{\mathrm{T}}$ So, temperature rises velocity also rises for string instruments $\mathrm{v}=\sqrt{\frac{\mathrm{T}}{\mathrm{mL}}} (\text { Where, } \mathrm{T} = \text { tension }$ $\mathrm{m} =\text { string mass }$ $\mathrm{L} =\text { string length }$ As temperature rises tension decreases as string slags So, velocity decreases in this case.
