What is the frequency (in reciprocal seconds) of electromagnetic radiation with a wavelength of 1.11 cm?

Two friends at different locations want to communicate with each other by sending low energy signals. which of the following methods can they use to communicate? a) produce x-rays using colliding electrons and send them to radios, which capture sound b) send messages using infrared radiation, which travel in the form of waves c) send radio waves through intervening media like radio and television d) produce sound waves using microwaves from heated objects

What is the empirical formula of vanadium 1 oxide given that 20.38 grams of vandium combines with oxygen to form 23.58 grams of the oxide

Which of the following is a physical property flammability heat of combustion solubility and toxicity