

Explanation
a)(i) Advantages of alcohol over mercury as a thermometric liquid are:
- Alcohol is cheaper
-Alcohol is easily available
-Alcohol has higher expansivity
- Alcohol has lower freezing point.
(ii) The glass bulb of the thermometer first got heated and expands, therefore the mercury level in it falls. Then the mercury expands and increases more than that of the glass and then rises.
(b) Factors that affect the rate of evaporation of a liquid, temperature exclusively are:
- Pressure, area of liquid surface exposed, humidity, nature of the liquid, wind and dryness of air, etc.
(c)(i) Q = mc
\(\Delta \theta = 100 \times 120 \times (320 - 40)\)
ii) Q = Ml = 100 x 0.25 x 10\(^5)\) = 2500000J
= 2.5MJ
ii) Pt = ml
t = \(\frac{ml}{p} = \frac{2500000}{10000} = 250s\)
(d) Precautions to be considered are:
- Calorimeter should be well lagged.
- Use only dry steam.
- Stir the mixture gently and continually.
- Shield the calorimeter from heat sources.

