<span>The formula for frequency is speed of light divided by wavelength. 650 nm represents the wavelength and 3x10^8 m/s is the speed of light. If you convert 650nm to meters you get 6.5x10^-7 m so you can divide using the formula above, giving you 4.6x10^14 1/s or Hz, the unit of frequency in Physics.</span>
C is incorrect because the atomic number and symbol are the only ones displayed.
I think it could be A but it is most likely C
Hope it helps!!
Answer:

Explanation:
Given that


Emissivity of surfaces(∈) = 1
We know that heat transfer between two surfaces due to radiation ,when both surfaces are black bodies

So now by putting the values



So rate of heat transfer per unit area

Answer:
The magnets need to be placed with red closest to blue.
Opposite poles attract.
The magnets will be attracted to each other with enough force to stick together.
Explanation: