physics mc (heat)1

1. A waterfall has a height of 60 m. Assuming no heat is lost from the water to the surroundings, estimate the difference in water temperature between the top and the bottom of the watterfall. (specific heat capacity of water=4200J/kg/K)


A 0.14(degree celcius)
B 0.7 (same)
C 1.4 (same)
D 7 (same)

Ans is A.


2. when mixing two cups of water of different temperatures together, which of the followings will always occur?

(1) The temperature drop of the hotter one will always be equal to the temperature rise of the cooler one.

(2) The energy lost of the hotter one will always be equal to the energy gained by the cooler one.

(3) This is an example of heating.

A (1) only
B (2) only
C (1) and (3) only
D (2) and (3) only

Ans is D

2題個ans點解會係咁?
第2題我答左A,點解錯?