The process of flask becoming cold is due to endothermic reaction.
Answer: Option B
<u>Explanation:</u>
So two kinds of heat transfer can be possible in any chemical reaction. If the sample is considered as system and the sample container is considered as the surrounding, then heat transfer can occur between them.
If the heat is transferred from the surrounding to the system , then it is an endothermic reaction. And in those cases, the sample holder will be becoming colder. This is because the heat from the surrounding that is the container will be utilized to complete the reaction.
While when there is transfer of heat from the system to surrounding , it will be exothermic reaction and the beaker will be getting hot in this process. So in the present case, the container is becoming cold because of occurrence of endothermic process.
Answer:
4.1 m
Explanation:
10 kW = 10000 W
20mi/h = 20*1.6 km/mi = 32 km/h = 32 * 1000 (m/km) *(1/3600) hr/s = 8.89 m/s
The power yielded by the wind turbine can be calculated using the following formula
where 
is the air density, v = 8.89 m/s is the wind speed, A is the swept area and 
is the efficiency
The swept area is a circle with radius r being the blade length
Photon energy is directly proportional to the frequency of electromagnetic radiation.
(That would also mean that it's inversely proportional to the wavelength.)
So the photon energy increases as you scan the chart of visible colors
moving from the red end of the rainbow to the blue end.
