I really don't get what the top box is asking me what to do

Step-by-step explanation:

The circle has a circumference:

This the is arc of full length θ = 360°

Each degree of arc length is:

We have:

The arc length is:

The same arc is:

probability for j is 1/4

while

a is 1/6

explanation:

infrared radiation has wavelength in the range between 700 nm and 1 mm. lets' convert these values into scientific notation, keeping in mind that:

let's start from the lower value, we have:

(we moved the dot two places to the left, so we increased the exponent by 2 units, from -9 to -7)

the higher value is:

so, the range of wavelength of infrared radiation is: