Question

Assertion : When hot water is poured in a beaker of thick glass, the beaker cracks.

Reason : Outer surface of the beaker expands suddenly.

(a) Both A and R are true and R is the correct explanation of A

(b) Both A and R are true but R is not correct explanation of A

(c) A is true but R is false

(d) A and R are false

Answer 1

Correct option (c) A is true but R is false

Explanation :

When we pour hot water in beaker, the inner surface of the glass expands on heating. But heat from inside does not reach quickly the outer surface of the glass, because glass is a bad conductor of heat. Hence, the outer surface does not expand and the glass cracks.