369929
Assertion : Glassy solids have sharp melting point. Reason : The bonds between the atoms of glassy solids break at the different values of temperature.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Glass is not ordered solid. i.e., not crystalline. In a glassy or amorphous solid, the bonds between its constituent atoms, ions, or molecules do not possess uniform strength. These various bonds break at different temperature levels \(\Rightarrow\) glass does not have sharp m.p. (melting point). So correct option is (4).
PHXI09:MECHANICAL PROPERTIES OF SOLIDS
369930
The potential energy \(U\) between two molecules as a function of the distance \(X\) between them has been shown in the figure. The two molecules are
1 Attracted when \(X\) lies between \(A\) and \(B\) and are repelled when \(X\) lies between \(B\) and \(C\)
2 Attracted when \(\mathrm{X}\) lies between \(B\) and \(C\) and are repelled when \(X\) lies between \(\mathrm{A}\) and \(B\)
3 Attracted when they reach \(A\)
4 Repelled when they reach \(C\)
Explanation:
\(F = - \left( {\frac{{dU}}{{dx}}} \right)\) In the region \(BC\), \(\frac{{dU}}{{dx}}\) is positive. \(\therefore \) \(F = \) negative, i.e., force is attractive in nature In the region \(AB\), \(\frac{{dU}}{{dx}}\) is negative. \(\therefore \) \(F = \) positive, i.e., force is repulsive in nature.
PHXI09:MECHANICAL PROPERTIES OF SOLIDS
369931
Statement A : In spring block model, displace it from its equilibrium position the spring system tries to restore it back to its original position. Statement B : The elastic behaviour of solids can be explained in terms of microscopic nature of the solid.
1 Statement A is correct but Statement B is incorrect.
2 Statement A is incorrect but Statement B is correct.
3 Both statements are correct.
4 Both Statements are incorrect.
Explanation:
When the deforming force is removed the interatomic forces tend to drive them back to their original positions. Option (3) is correct.
PHXI09:MECHANICAL PROPERTIES OF SOLIDS
369932
The point of maximum and minimum attraction in the curve between potential energy \((U)\) and distance \((r)\) of a diatomic molecule are respectively.
1 \(T\,{\text{and}}\,S\)
2 \(S{\text{ and }}T\)
3 \(P{\text{ and }}Q\)
4 \(R{\text{ and }}S\)
Explanation:
The relation between force and potential energy is \(F=-\left(\dfrac{d U}{d x}\right)\) In the region between \(T\,{\text{and}}\,R\) \(\dfrac{d U}{d x}=(+) v e \Rightarrow F=-\dfrac{d U}{d x}=(-) v e\) In the region between \(P{\mkern 1mu} {\text{and}}{\mkern 1mu} R\) \(\dfrac{d U}{d x}=(-) v e \Rightarrow F=-\dfrac{d U}{d x}=(+) v e\) The region between \(T\) and \(R\) is attractive and between \(P\) and \(R\) is repulsive. At-R \(R \dfrac{d U}{d x}=0 \Rightarrow F=0\) and the molecule is in equilibrium. At-S \(\begin{aligned}& S \dfrac{d U}{d x}=(+) v e \\\Rightarrow & F=-\dfrac{d U}{d x}=-(v e)\end{aligned}\) The slope \(\dfrac{d U}{d x}\) is maximum at \(S\) and minimum at \(T\). Attractive force is maximum at \(\mathrm{S}\) and minimum at \(T\).
369929
Assertion : Glassy solids have sharp melting point. Reason : The bonds between the atoms of glassy solids break at the different values of temperature.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Glass is not ordered solid. i.e., not crystalline. In a glassy or amorphous solid, the bonds between its constituent atoms, ions, or molecules do not possess uniform strength. These various bonds break at different temperature levels \(\Rightarrow\) glass does not have sharp m.p. (melting point). So correct option is (4).
PHXI09:MECHANICAL PROPERTIES OF SOLIDS
369930
The potential energy \(U\) between two molecules as a function of the distance \(X\) between them has been shown in the figure. The two molecules are
1 Attracted when \(X\) lies between \(A\) and \(B\) and are repelled when \(X\) lies between \(B\) and \(C\)
2 Attracted when \(\mathrm{X}\) lies between \(B\) and \(C\) and are repelled when \(X\) lies between \(\mathrm{A}\) and \(B\)
3 Attracted when they reach \(A\)
4 Repelled when they reach \(C\)
Explanation:
\(F = - \left( {\frac{{dU}}{{dx}}} \right)\) In the region \(BC\), \(\frac{{dU}}{{dx}}\) is positive. \(\therefore \) \(F = \) negative, i.e., force is attractive in nature In the region \(AB\), \(\frac{{dU}}{{dx}}\) is negative. \(\therefore \) \(F = \) positive, i.e., force is repulsive in nature.
PHXI09:MECHANICAL PROPERTIES OF SOLIDS
369931
Statement A : In spring block model, displace it from its equilibrium position the spring system tries to restore it back to its original position. Statement B : The elastic behaviour of solids can be explained in terms of microscopic nature of the solid.
1 Statement A is correct but Statement B is incorrect.
2 Statement A is incorrect but Statement B is correct.
3 Both statements are correct.
4 Both Statements are incorrect.
Explanation:
When the deforming force is removed the interatomic forces tend to drive them back to their original positions. Option (3) is correct.
PHXI09:MECHANICAL PROPERTIES OF SOLIDS
369932
The point of maximum and minimum attraction in the curve between potential energy \((U)\) and distance \((r)\) of a diatomic molecule are respectively.
1 \(T\,{\text{and}}\,S\)
2 \(S{\text{ and }}T\)
3 \(P{\text{ and }}Q\)
4 \(R{\text{ and }}S\)
Explanation:
The relation between force and potential energy is \(F=-\left(\dfrac{d U}{d x}\right)\) In the region between \(T\,{\text{and}}\,R\) \(\dfrac{d U}{d x}=(+) v e \Rightarrow F=-\dfrac{d U}{d x}=(-) v e\) In the region between \(P{\mkern 1mu} {\text{and}}{\mkern 1mu} R\) \(\dfrac{d U}{d x}=(-) v e \Rightarrow F=-\dfrac{d U}{d x}=(+) v e\) The region between \(T\) and \(R\) is attractive and between \(P\) and \(R\) is repulsive. At-R \(R \dfrac{d U}{d x}=0 \Rightarrow F=0\) and the molecule is in equilibrium. At-S \(\begin{aligned}& S \dfrac{d U}{d x}=(+) v e \\\Rightarrow & F=-\dfrac{d U}{d x}=-(v e)\end{aligned}\) The slope \(\dfrac{d U}{d x}\) is maximum at \(S\) and minimum at \(T\). Attractive force is maximum at \(\mathrm{S}\) and minimum at \(T\).
369929
Assertion : Glassy solids have sharp melting point. Reason : The bonds between the atoms of glassy solids break at the different values of temperature.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Glass is not ordered solid. i.e., not crystalline. In a glassy or amorphous solid, the bonds between its constituent atoms, ions, or molecules do not possess uniform strength. These various bonds break at different temperature levels \(\Rightarrow\) glass does not have sharp m.p. (melting point). So correct option is (4).
PHXI09:MECHANICAL PROPERTIES OF SOLIDS
369930
The potential energy \(U\) between two molecules as a function of the distance \(X\) between them has been shown in the figure. The two molecules are
1 Attracted when \(X\) lies between \(A\) and \(B\) and are repelled when \(X\) lies between \(B\) and \(C\)
2 Attracted when \(\mathrm{X}\) lies between \(B\) and \(C\) and are repelled when \(X\) lies between \(\mathrm{A}\) and \(B\)
3 Attracted when they reach \(A\)
4 Repelled when they reach \(C\)
Explanation:
\(F = - \left( {\frac{{dU}}{{dx}}} \right)\) In the region \(BC\), \(\frac{{dU}}{{dx}}\) is positive. \(\therefore \) \(F = \) negative, i.e., force is attractive in nature In the region \(AB\), \(\frac{{dU}}{{dx}}\) is negative. \(\therefore \) \(F = \) positive, i.e., force is repulsive in nature.
PHXI09:MECHANICAL PROPERTIES OF SOLIDS
369931
Statement A : In spring block model, displace it from its equilibrium position the spring system tries to restore it back to its original position. Statement B : The elastic behaviour of solids can be explained in terms of microscopic nature of the solid.
1 Statement A is correct but Statement B is incorrect.
2 Statement A is incorrect but Statement B is correct.
3 Both statements are correct.
4 Both Statements are incorrect.
Explanation:
When the deforming force is removed the interatomic forces tend to drive them back to their original positions. Option (3) is correct.
PHXI09:MECHANICAL PROPERTIES OF SOLIDS
369932
The point of maximum and minimum attraction in the curve between potential energy \((U)\) and distance \((r)\) of a diatomic molecule are respectively.
1 \(T\,{\text{and}}\,S\)
2 \(S{\text{ and }}T\)
3 \(P{\text{ and }}Q\)
4 \(R{\text{ and }}S\)
Explanation:
The relation between force and potential energy is \(F=-\left(\dfrac{d U}{d x}\right)\) In the region between \(T\,{\text{and}}\,R\) \(\dfrac{d U}{d x}=(+) v e \Rightarrow F=-\dfrac{d U}{d x}=(-) v e\) In the region between \(P{\mkern 1mu} {\text{and}}{\mkern 1mu} R\) \(\dfrac{d U}{d x}=(-) v e \Rightarrow F=-\dfrac{d U}{d x}=(+) v e\) The region between \(T\) and \(R\) is attractive and between \(P\) and \(R\) is repulsive. At-R \(R \dfrac{d U}{d x}=0 \Rightarrow F=0\) and the molecule is in equilibrium. At-S \(\begin{aligned}& S \dfrac{d U}{d x}=(+) v e \\\Rightarrow & F=-\dfrac{d U}{d x}=-(v e)\end{aligned}\) The slope \(\dfrac{d U}{d x}\) is maximum at \(S\) and minimum at \(T\). Attractive force is maximum at \(\mathrm{S}\) and minimum at \(T\).
369929
Assertion : Glassy solids have sharp melting point. Reason : The bonds between the atoms of glassy solids break at the different values of temperature.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Glass is not ordered solid. i.e., not crystalline. In a glassy or amorphous solid, the bonds between its constituent atoms, ions, or molecules do not possess uniform strength. These various bonds break at different temperature levels \(\Rightarrow\) glass does not have sharp m.p. (melting point). So correct option is (4).
PHXI09:MECHANICAL PROPERTIES OF SOLIDS
369930
The potential energy \(U\) between two molecules as a function of the distance \(X\) between them has been shown in the figure. The two molecules are
1 Attracted when \(X\) lies between \(A\) and \(B\) and are repelled when \(X\) lies between \(B\) and \(C\)
2 Attracted when \(\mathrm{X}\) lies between \(B\) and \(C\) and are repelled when \(X\) lies between \(\mathrm{A}\) and \(B\)
3 Attracted when they reach \(A\)
4 Repelled when they reach \(C\)
Explanation:
\(F = - \left( {\frac{{dU}}{{dx}}} \right)\) In the region \(BC\), \(\frac{{dU}}{{dx}}\) is positive. \(\therefore \) \(F = \) negative, i.e., force is attractive in nature In the region \(AB\), \(\frac{{dU}}{{dx}}\) is negative. \(\therefore \) \(F = \) positive, i.e., force is repulsive in nature.
PHXI09:MECHANICAL PROPERTIES OF SOLIDS
369931
Statement A : In spring block model, displace it from its equilibrium position the spring system tries to restore it back to its original position. Statement B : The elastic behaviour of solids can be explained in terms of microscopic nature of the solid.
1 Statement A is correct but Statement B is incorrect.
2 Statement A is incorrect but Statement B is correct.
3 Both statements are correct.
4 Both Statements are incorrect.
Explanation:
When the deforming force is removed the interatomic forces tend to drive them back to their original positions. Option (3) is correct.
PHXI09:MECHANICAL PROPERTIES OF SOLIDS
369932
The point of maximum and minimum attraction in the curve between potential energy \((U)\) and distance \((r)\) of a diatomic molecule are respectively.
1 \(T\,{\text{and}}\,S\)
2 \(S{\text{ and }}T\)
3 \(P{\text{ and }}Q\)
4 \(R{\text{ and }}S\)
Explanation:
The relation between force and potential energy is \(F=-\left(\dfrac{d U}{d x}\right)\) In the region between \(T\,{\text{and}}\,R\) \(\dfrac{d U}{d x}=(+) v e \Rightarrow F=-\dfrac{d U}{d x}=(-) v e\) In the region between \(P{\mkern 1mu} {\text{and}}{\mkern 1mu} R\) \(\dfrac{d U}{d x}=(-) v e \Rightarrow F=-\dfrac{d U}{d x}=(+) v e\) The region between \(T\) and \(R\) is attractive and between \(P\) and \(R\) is repulsive. At-R \(R \dfrac{d U}{d x}=0 \Rightarrow F=0\) and the molecule is in equilibrium. At-S \(\begin{aligned}& S \dfrac{d U}{d x}=(+) v e \\\Rightarrow & F=-\dfrac{d U}{d x}=-(v e)\end{aligned}\) The slope \(\dfrac{d U}{d x}\) is maximum at \(S\) and minimum at \(T\). Attractive force is maximum at \(\mathrm{S}\) and minimum at \(T\).
