Well, with the light spectrum there technically is no middle color. Both green and yellow meet up in the middle at 560 nm (wavelength interval) and 540 THz (frequency interval).
Good afternoon!
We calculate the volume of the container in cm³. To do that, we must put the units in cm:
30 cm → 30 cm
50 mm → 5 cm
0.2 m → 20 cm
The volume is:
V = 30 . 5 . 20
V = 3000 cm³
Now, we calculate the mas with the formula:
m = dV
m = 2.5 · 3000
m = 7500 g
Dividing by 1000, we have the mass in kg:
m = 7.5 kg
Cp shows the amount of energy needed to raise temperature by one degree for one gram of water.
Formula for calculating cp is:

Final temperature is 26.73°C.
The correct answer to this Electric current.