Craig has £13.40 He sees this offer in a restaurant:

Main courses £8.90 each. Buy one main course and get the 2nd HALF PRICE!

Can he afford to buy two main courses? Show your working.

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: