Answer:
Im not 100% sure but i think the answer is A. An electron in an atom jumping from a lower energy state to a higher one.
Explanation:
lmk if its wrong
The work done by Joe is 0 J.
<u>Explanation</u>:
When a force is applied to an object, there will be a movement because of the applied force to a certain distance. This transfer of energy when a force is applied to an object that tends to move the object is known as work done.
The energy is transferred from one state to another and the stored energy is equal to the work done.
W = F . D
where F represents the force in newton,
D represents the distance or displacement of an object.
Force = 0 N, D = 20 cm = 0.20 m
W = 0
0.20 = 0 J.
Hence the work done by Joe is 0 J.
<u>Answer:</u> The elevation in boiling point is 1.024°C.
<u>Explanation:</u>
To calculate the elevation in boiling point, we use the equation:

where,
i = Van't Hoff factor = 2 (for NaCl)
= change in boiling point = ?
= boiling point constant = 
m = molality = 1.0 m
Putting values in above equation, we get:

Hence, the elevation in boiling point is 1.024°C.
Answer:
The rate of heat conduction through the layer of still air is 517.4 W
Explanation:
Given:
Thickness of the still air layer (L) = 1 mm
Area of the still air = 1 m
Temperature of the still air ( T) = 20°C
Thermal conductivity of still air (K) at 20°C = 25.87mW/mK
Rate of heat conduction (Q) = ?
To determine the rate of heat conduction through the still air, we apply the formula below.


Q = 517.4 W
Therefore, the rate of heat conduction through the layer of still air is 517.4 W