A group goes vertically and a period goes horizontally.
(a group goes down and a period goes across)
The state of matter is liquid.
Answer:
One of the main uses of the cathode ray tube is in the Cathode ray oscilloscope
Explanation:
Cathode rays are produced when a gas in an evacuated glass at very low pressure and high pressure breaks up into positive and negative ions. the negative ions move towards the anode(positive electrode) while the positive ions move towards the cathode(negative electrode), and there they knock off electrons (which are known as cathode rays) from the metal plate of the cathode.
Cathode ray tubes are mainly used in oscilloscopes, television picture tubes and in computer screens.
The cathode ray oscilloscope is used in a.c. and d.c. voltage measurements, observation of waveforms, time measurements, etc.
D. a compound can only be separated into its components by chemical means
Answer:
The answer is

Explanation:
The energy of a quantum of light can be found by using the formula
<h3>E = hf</h3>
where
E is the energy
f is the frequency
h is the Planck's constant which is
6.626 × 10-³⁴ Js
From the question
f = 4.31 × 10¹⁴ Hz
We have
E = 4.31 × 10¹⁴ × 6.626 × 10-³⁴
We have the final answer as

Hope this helps you