I think it’s ultraviolet, if not i’m sorry!
Answer:
Part a) 
Part b) 
Explanation:
Part a) what is its frequency, in rev/s
we have that
An old-fashioned LP record rotates at 33 1/3 RPM
so

Convert mixed number to an improper fraction

Remember that

Convert rev/min to rev/sec

Simplify

Part b) what is it period, in seconds
we know that
The period is the reciprocal of the frequency
therefore
the frequency is

Answer:
Three types of electromagnetic waves, used to transmit various information
Explanation:
A form of energy waves having both electric & magnetic fields are Electromagnetic waves. Three types -
Radio Waves - These have longest wavelengths & transmit data through radio, satellites, radar .
Micro Waves - These have shorter wavelengths & are used in cooking appliances & predicting weather.
X rays - These have more short wavelength and can penerate soft tissues like skin & muscle, hence are used for medical examining
Answer:
Given
Frequency (f) = 3Hz
Wavelength = 9 m
Speed = ?
Explanation:
we know
Speed = wavelength * frequency
= 9*3
= 27 m/ s