Answer:
Here's what I get.
Explanation:
(b) Wavenumber and wavelength
The wavenumber is the distance over which a cycle repeats, that is, it is the number of waves in a unit distance.

Thus, if λ = 3 µm,

(a) Wavenumber and frequency
Since
λ = c/f and 1/λ = f/c
the relation between wavenumber and frequency is

Thus, if f = 90 THz

(c) Units
(i) Frequency
The units are s⁻¹ or Hz.
(ii) Wavelength
The SI base unit is metres, but infrared wavelengths are usually measured in micrometres (roughly 2.5 µm to 20 µm).
(iii) Wavenumber
The SI base unit is m⁻¹, but infrared wavenumbers are usually measured in cm⁻¹ (roughly 4000 cm⁻¹ to 500 cm⁻¹).
Answer: I think it's C
Explanation: I hope this helps (Sorry if it doesn't)
Answer:
This is a chemical change because it has been lit on fire. When it is lit on fire, the fire has been made, heat has been made, and gasses produced from the fire have also been made. Because this introduces new matter to the pictures, it is a chemical reaction.
Explanation: