Page 3 - HOME ASSIGNMENT-3(PRACTICAL WS)

5. At room temperature a student sets up an apparatus to determine the melting point of
ice. He takes a beaker half filled with crushed ice and dips a mercury thermometer in it.
After this he would observe that:
(a) mercury in the thermometer keeps on falling till it reads – 1 °C, it remains constant
thereafter
(b) temperature falls, reaches 0°C and remains constant only as long as both ice and
water are present in it
(c) the temperature falls, reaches 0°C and remains constant even after the whole of ice
has melted
(d) the temperature falls at the starting but starts rising as soon as the ice starts melting.

6. A thermometer has 20 equal divisions between 90°C and 100°C mark. A student while
determining the boiling point of water finds that the mercury thread becomes stationary
at the 19th mark above 90°C. He should record the boiling point of water as:
(a) 90.19°C
(b) 99.5°C
(c) 109°C
(d) 119°C.

7. What is not a correct precaution to be followed by a student to determine the melting
point of ice?
(a) Zero mark of the thermometer should remain above the ice surface
(b) Keep stirring the mixture and look at the thermometer
(c) Crush the ice into small pieces
(d) Do not dip the thermometer in crushed ice.
8. Which of the following would you choose to determine the melting point of ice in your
laboratory?
(a) Dry crushed ice
(b) Ice cubes
(c) Ice added to water
(d) Slab of ice.

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