172802
Assertion: Sound travels faster in solids than gases. Reason: Solids possess greater density then gases.
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:
B Sound travels faster in solids than gases because the elasticity of solid is greater than that of gases. $\because \quad \mathrm{v}=\sqrt{\frac{\mathrm{E}}{\rho}}$ Velocity is directly proportional to the elasticity. Since the solid possesses greater elasticity than the gases, the vibration of the sound waves is maximum in it. Hence, the sound wave travels faster in the solid. The solid is denser than the gases so reason is also correct. In case of solid, its elasticity for exceeds that of gas so its effect far exceeds the effect of density.
AIIMS-2004
WAVES
172803
A person speaking normally produces a sound intensity of $40 \mathrm{~dB}$ at a distance of $1 \mathrm{~m}$. If the threshold intensity for reasonable audibility is $20 \mathrm{~dB}$, the maximum distance at which he can be heard clearly is
1 $4 \mathrm{~m}$
2 $5 \mathrm{~m}$
3 $10 \mathrm{~m}$
4 $20 \mathrm{~m}$
Explanation:
C Since, we know that loudness of sound, $\mathrm{dB}=10 \log _{10}\left(\frac{\mathrm{I}}{\mathrm{I}_{0}}\right)$ Where, $I_{0}$ threshold intensity of sound $=10^{-12} \mathrm{~W} / \mathrm{m}^{2}$ $10 \log _{10}\left(\frac{I_{1}}{I_{0}}\right)=40$ $10 \log _{10}\left(\frac{\mathrm{I}_{2}}{\mathrm{I}_{0}}\right)=20$ On dividing equation (i) and (ii), we get - $\frac{40}{20}=\log _{10}\left(\frac{I_{1}}{I_{2}}\right)$ $2=\log _{10} \frac{I_{1}}{I_{2}}$ $\frac{\mathrm{I}_{1}}{\mathrm{I}_{2}}=10^{2}=100$ $\because \quad \mathrm{I} \propto \frac{1}{\mathrm{r}^{2}}$ $\Rightarrow \quad \frac{\mathrm{I}_{1}}{\mathrm{I}_{2}}=\frac{\mathrm{r}_{2}^{2}}{\mathrm{r}_{1}^{2}}$ $\therefore \quad \frac{\mathrm{r}_{2}}{\mathrm{r}_{1}}=10$ $\mathrm{r}_{2}=10 \mathrm{r}_{1}=10 \times 1=10 \mathrm{~m}$ $\mathrm{r}_{2}=10 \mathrm{~m}$
AIIMS-2008
WAVES
172804
A siren emitting sound of frequency $800 \mathrm{~Hz}$ is going away from a static listener with a speed of $30 \mathrm{~m} / \mathrm{s}$. Frequency of the sound to be heard by the listener is (Take velocity of sound = $330 \mathrm{~m} / \mathrm{s}$ )
1 $286.5 \mathrm{~Hz}$
2 $481.2 \mathrm{~Hz}$
3 $733.3 \mathrm{~Hz}$
4 $644.8 \mathrm{~Hz}$
Explanation:
C Given, frequency of source $\mathrm{f}_{\mathrm{o}}=800 \mathrm{~Hz}$ Speed of emitted sound, $\mathrm{v}_{\mathrm{s}}=30 \mathrm{~m} / \mathrm{s}$ Velocity of sound $(\mathrm{v})=330 \mathrm{~m} / \mathrm{s}$ Frequency heard by observer, $\mathrm{f}=$ ? We know that, $f=f_{o}\left[\frac{v}{v+v_{s}}\right]$ $f=800\left[\frac{330}{330+30}\right]$ $f=800 \times \frac{330}{360}$ $f=733.3 \mathrm{~Hz}$
AIIMS-2002
WAVES
172799
Assertion: Sound waves cannot travel in vacuum but light can travel in vacuum. Reason: Sound waves are longitudinal waves and they cannot be polarised but electromagnetic wave are transverse and they can be polarised.
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:
B Transverse wave can be polarized. Light wave is transverse in nature but sound wave is longitudinal in nature. So former can polarized but later can not be. Moreover sound wave required material medium for its propagation but light wave being electromagnetic, it doesn't require any material medium for its propagation. Hence, Assertion and Reasons are individually correct but Reasons is not correct explanation of Assertion.
172802
Assertion: Sound travels faster in solids than gases. Reason: Solids possess greater density then gases.
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:
B Sound travels faster in solids than gases because the elasticity of solid is greater than that of gases. $\because \quad \mathrm{v}=\sqrt{\frac{\mathrm{E}}{\rho}}$ Velocity is directly proportional to the elasticity. Since the solid possesses greater elasticity than the gases, the vibration of the sound waves is maximum in it. Hence, the sound wave travels faster in the solid. The solid is denser than the gases so reason is also correct. In case of solid, its elasticity for exceeds that of gas so its effect far exceeds the effect of density.
AIIMS-2004
WAVES
172803
A person speaking normally produces a sound intensity of $40 \mathrm{~dB}$ at a distance of $1 \mathrm{~m}$. If the threshold intensity for reasonable audibility is $20 \mathrm{~dB}$, the maximum distance at which he can be heard clearly is
1 $4 \mathrm{~m}$
2 $5 \mathrm{~m}$
3 $10 \mathrm{~m}$
4 $20 \mathrm{~m}$
Explanation:
C Since, we know that loudness of sound, $\mathrm{dB}=10 \log _{10}\left(\frac{\mathrm{I}}{\mathrm{I}_{0}}\right)$ Where, $I_{0}$ threshold intensity of sound $=10^{-12} \mathrm{~W} / \mathrm{m}^{2}$ $10 \log _{10}\left(\frac{I_{1}}{I_{0}}\right)=40$ $10 \log _{10}\left(\frac{\mathrm{I}_{2}}{\mathrm{I}_{0}}\right)=20$ On dividing equation (i) and (ii), we get - $\frac{40}{20}=\log _{10}\left(\frac{I_{1}}{I_{2}}\right)$ $2=\log _{10} \frac{I_{1}}{I_{2}}$ $\frac{\mathrm{I}_{1}}{\mathrm{I}_{2}}=10^{2}=100$ $\because \quad \mathrm{I} \propto \frac{1}{\mathrm{r}^{2}}$ $\Rightarrow \quad \frac{\mathrm{I}_{1}}{\mathrm{I}_{2}}=\frac{\mathrm{r}_{2}^{2}}{\mathrm{r}_{1}^{2}}$ $\therefore \quad \frac{\mathrm{r}_{2}}{\mathrm{r}_{1}}=10$ $\mathrm{r}_{2}=10 \mathrm{r}_{1}=10 \times 1=10 \mathrm{~m}$ $\mathrm{r}_{2}=10 \mathrm{~m}$
AIIMS-2008
WAVES
172804
A siren emitting sound of frequency $800 \mathrm{~Hz}$ is going away from a static listener with a speed of $30 \mathrm{~m} / \mathrm{s}$. Frequency of the sound to be heard by the listener is (Take velocity of sound = $330 \mathrm{~m} / \mathrm{s}$ )
1 $286.5 \mathrm{~Hz}$
2 $481.2 \mathrm{~Hz}$
3 $733.3 \mathrm{~Hz}$
4 $644.8 \mathrm{~Hz}$
Explanation:
C Given, frequency of source $\mathrm{f}_{\mathrm{o}}=800 \mathrm{~Hz}$ Speed of emitted sound, $\mathrm{v}_{\mathrm{s}}=30 \mathrm{~m} / \mathrm{s}$ Velocity of sound $(\mathrm{v})=330 \mathrm{~m} / \mathrm{s}$ Frequency heard by observer, $\mathrm{f}=$ ? We know that, $f=f_{o}\left[\frac{v}{v+v_{s}}\right]$ $f=800\left[\frac{330}{330+30}\right]$ $f=800 \times \frac{330}{360}$ $f=733.3 \mathrm{~Hz}$
AIIMS-2002
WAVES
172799
Assertion: Sound waves cannot travel in vacuum but light can travel in vacuum. Reason: Sound waves are longitudinal waves and they cannot be polarised but electromagnetic wave are transverse and they can be polarised.
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:
B Transverse wave can be polarized. Light wave is transverse in nature but sound wave is longitudinal in nature. So former can polarized but later can not be. Moreover sound wave required material medium for its propagation but light wave being electromagnetic, it doesn't require any material medium for its propagation. Hence, Assertion and Reasons are individually correct but Reasons is not correct explanation of Assertion.
172802
Assertion: Sound travels faster in solids than gases. Reason: Solids possess greater density then gases.
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:
B Sound travels faster in solids than gases because the elasticity of solid is greater than that of gases. $\because \quad \mathrm{v}=\sqrt{\frac{\mathrm{E}}{\rho}}$ Velocity is directly proportional to the elasticity. Since the solid possesses greater elasticity than the gases, the vibration of the sound waves is maximum in it. Hence, the sound wave travels faster in the solid. The solid is denser than the gases so reason is also correct. In case of solid, its elasticity for exceeds that of gas so its effect far exceeds the effect of density.
AIIMS-2004
WAVES
172803
A person speaking normally produces a sound intensity of $40 \mathrm{~dB}$ at a distance of $1 \mathrm{~m}$. If the threshold intensity for reasonable audibility is $20 \mathrm{~dB}$, the maximum distance at which he can be heard clearly is
1 $4 \mathrm{~m}$
2 $5 \mathrm{~m}$
3 $10 \mathrm{~m}$
4 $20 \mathrm{~m}$
Explanation:
C Since, we know that loudness of sound, $\mathrm{dB}=10 \log _{10}\left(\frac{\mathrm{I}}{\mathrm{I}_{0}}\right)$ Where, $I_{0}$ threshold intensity of sound $=10^{-12} \mathrm{~W} / \mathrm{m}^{2}$ $10 \log _{10}\left(\frac{I_{1}}{I_{0}}\right)=40$ $10 \log _{10}\left(\frac{\mathrm{I}_{2}}{\mathrm{I}_{0}}\right)=20$ On dividing equation (i) and (ii), we get - $\frac{40}{20}=\log _{10}\left(\frac{I_{1}}{I_{2}}\right)$ $2=\log _{10} \frac{I_{1}}{I_{2}}$ $\frac{\mathrm{I}_{1}}{\mathrm{I}_{2}}=10^{2}=100$ $\because \quad \mathrm{I} \propto \frac{1}{\mathrm{r}^{2}}$ $\Rightarrow \quad \frac{\mathrm{I}_{1}}{\mathrm{I}_{2}}=\frac{\mathrm{r}_{2}^{2}}{\mathrm{r}_{1}^{2}}$ $\therefore \quad \frac{\mathrm{r}_{2}}{\mathrm{r}_{1}}=10$ $\mathrm{r}_{2}=10 \mathrm{r}_{1}=10 \times 1=10 \mathrm{~m}$ $\mathrm{r}_{2}=10 \mathrm{~m}$
AIIMS-2008
WAVES
172804
A siren emitting sound of frequency $800 \mathrm{~Hz}$ is going away from a static listener with a speed of $30 \mathrm{~m} / \mathrm{s}$. Frequency of the sound to be heard by the listener is (Take velocity of sound = $330 \mathrm{~m} / \mathrm{s}$ )
1 $286.5 \mathrm{~Hz}$
2 $481.2 \mathrm{~Hz}$
3 $733.3 \mathrm{~Hz}$
4 $644.8 \mathrm{~Hz}$
Explanation:
C Given, frequency of source $\mathrm{f}_{\mathrm{o}}=800 \mathrm{~Hz}$ Speed of emitted sound, $\mathrm{v}_{\mathrm{s}}=30 \mathrm{~m} / \mathrm{s}$ Velocity of sound $(\mathrm{v})=330 \mathrm{~m} / \mathrm{s}$ Frequency heard by observer, $\mathrm{f}=$ ? We know that, $f=f_{o}\left[\frac{v}{v+v_{s}}\right]$ $f=800\left[\frac{330}{330+30}\right]$ $f=800 \times \frac{330}{360}$ $f=733.3 \mathrm{~Hz}$
AIIMS-2002
WAVES
172799
Assertion: Sound waves cannot travel in vacuum but light can travel in vacuum. Reason: Sound waves are longitudinal waves and they cannot be polarised but electromagnetic wave are transverse and they can be polarised.
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:
B Transverse wave can be polarized. Light wave is transverse in nature but sound wave is longitudinal in nature. So former can polarized but later can not be. Moreover sound wave required material medium for its propagation but light wave being electromagnetic, it doesn't require any material medium for its propagation. Hence, Assertion and Reasons are individually correct but Reasons is not correct explanation of Assertion.
172802
Assertion: Sound travels faster in solids than gases. Reason: Solids possess greater density then gases.
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:
B Sound travels faster in solids than gases because the elasticity of solid is greater than that of gases. $\because \quad \mathrm{v}=\sqrt{\frac{\mathrm{E}}{\rho}}$ Velocity is directly proportional to the elasticity. Since the solid possesses greater elasticity than the gases, the vibration of the sound waves is maximum in it. Hence, the sound wave travels faster in the solid. The solid is denser than the gases so reason is also correct. In case of solid, its elasticity for exceeds that of gas so its effect far exceeds the effect of density.
AIIMS-2004
WAVES
172803
A person speaking normally produces a sound intensity of $40 \mathrm{~dB}$ at a distance of $1 \mathrm{~m}$. If the threshold intensity for reasonable audibility is $20 \mathrm{~dB}$, the maximum distance at which he can be heard clearly is
1 $4 \mathrm{~m}$
2 $5 \mathrm{~m}$
3 $10 \mathrm{~m}$
4 $20 \mathrm{~m}$
Explanation:
C Since, we know that loudness of sound, $\mathrm{dB}=10 \log _{10}\left(\frac{\mathrm{I}}{\mathrm{I}_{0}}\right)$ Where, $I_{0}$ threshold intensity of sound $=10^{-12} \mathrm{~W} / \mathrm{m}^{2}$ $10 \log _{10}\left(\frac{I_{1}}{I_{0}}\right)=40$ $10 \log _{10}\left(\frac{\mathrm{I}_{2}}{\mathrm{I}_{0}}\right)=20$ On dividing equation (i) and (ii), we get - $\frac{40}{20}=\log _{10}\left(\frac{I_{1}}{I_{2}}\right)$ $2=\log _{10} \frac{I_{1}}{I_{2}}$ $\frac{\mathrm{I}_{1}}{\mathrm{I}_{2}}=10^{2}=100$ $\because \quad \mathrm{I} \propto \frac{1}{\mathrm{r}^{2}}$ $\Rightarrow \quad \frac{\mathrm{I}_{1}}{\mathrm{I}_{2}}=\frac{\mathrm{r}_{2}^{2}}{\mathrm{r}_{1}^{2}}$ $\therefore \quad \frac{\mathrm{r}_{2}}{\mathrm{r}_{1}}=10$ $\mathrm{r}_{2}=10 \mathrm{r}_{1}=10 \times 1=10 \mathrm{~m}$ $\mathrm{r}_{2}=10 \mathrm{~m}$
AIIMS-2008
WAVES
172804
A siren emitting sound of frequency $800 \mathrm{~Hz}$ is going away from a static listener with a speed of $30 \mathrm{~m} / \mathrm{s}$. Frequency of the sound to be heard by the listener is (Take velocity of sound = $330 \mathrm{~m} / \mathrm{s}$ )
1 $286.5 \mathrm{~Hz}$
2 $481.2 \mathrm{~Hz}$
3 $733.3 \mathrm{~Hz}$
4 $644.8 \mathrm{~Hz}$
Explanation:
C Given, frequency of source $\mathrm{f}_{\mathrm{o}}=800 \mathrm{~Hz}$ Speed of emitted sound, $\mathrm{v}_{\mathrm{s}}=30 \mathrm{~m} / \mathrm{s}$ Velocity of sound $(\mathrm{v})=330 \mathrm{~m} / \mathrm{s}$ Frequency heard by observer, $\mathrm{f}=$ ? We know that, $f=f_{o}\left[\frac{v}{v+v_{s}}\right]$ $f=800\left[\frac{330}{330+30}\right]$ $f=800 \times \frac{330}{360}$ $f=733.3 \mathrm{~Hz}$
AIIMS-2002
WAVES
172799
Assertion: Sound waves cannot travel in vacuum but light can travel in vacuum. Reason: Sound waves are longitudinal waves and they cannot be polarised but electromagnetic wave are transverse and they can be polarised.
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:
B Transverse wave can be polarized. Light wave is transverse in nature but sound wave is longitudinal in nature. So former can polarized but later can not be. Moreover sound wave required material medium for its propagation but light wave being electromagnetic, it doesn't require any material medium for its propagation. Hence, Assertion and Reasons are individually correct but Reasons is not correct explanation of Assertion.
