Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason R.
Assertion A : Sharp glass edge becomes smooth on heating it upto its melting point.
Reason R : The viscosity of glass decreases on melting.
Choose the most appropriate answer from the options given below.
Assertion A : Sharp glass edge becomes smooth on heating it upto its melting point.
Reason R : The viscosity of glass decreases on melting.
Choose the most appropriate answer from the options given below.
Show Hint
- A is true but R is false
- Both A and R are true but R is NOT the correct explanation of A.
- A is false but R is true.
- Both A and R are true and R is the correct explanation of A.
The Correct Option is D
Solution and Explanation
Reason R is true: glass is an amorphous solid with no sharp melting point; on heating it softens and its viscosity drops sharply.
Because the viscosity falls, the softened glass can flow under surface tension, and the sharp edge flows into a smooth rounded surface. So R directly explains A.
Answer: (4) Both A and R are true and R is the correct explanation of A.
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