Answer:
The relation between frequency and time period is given by:
f = 1/T
Explanation:
In a wave motion, the particle move about the mean position with the passage of time. The particles rise to reach the highest point which is crest, and similarly falls to reach the lowest point which is trough. The cycle keeps on repeating.
The time period of the wave can be defined as the time taken to complete one such cycle. Time period is given by:
T = 2π/ω
Frequency can be defined as the number of cycles completed in unit time, which can be taken as the inverse of time period. frequency is given by
f = ω/2π
or
f = 1/T
Many devices have been invented to accurately measure temperature. It all started with the establishment of a temperature scale. This scale transformed the measurement of temperature into meaningful numbers.
In the early years of the eighteenth century, Gabriel Fahrenheit (1686-1736) created the Fahrenheit scale. He set the freezing point of water at 32 degrees and the boiling point at 212 degrees. These two points formed the anchors for his scale.
Later in that century, around 1743, Anders Celsius (1701-1744) invented the Celsius scale. Using the same anchor points, he determined the freezing temperature for water to be 0 degree and the boiling temperature 100 degrees. The Celsius scale is known as a Universal System Unit. It is used throughout science and in most countries.
There is a limit to how cold something can be. The Kelvin scale is designed to go to zero at this minimum temperature. The relationships between the different temperature scales are:
oK = 273.15 + oC oC = (5/9)*(oF-32) oF = (9/5)*oC+32
oF oC oK
Water boils 212 100 373
Room Temperature 72 23 296
Water Freezes 32 0 273
Absolute Zero -460 -273 0
At a temperature of Absolute Zero there is no motion and no heat. Absolute zero is where all atomic and molecular motion stops and is the lowest temperature possible. Absolute Zero occurs at 0 degrees Kelvin or -273.15 degrees Celsius or at -460 degrees Fahrenheit. All objects emit thermal energy or heat unless they have a temperature of absolute zero.
If we want to understand what temperature means on the molecular level, we should remember that temperature is the average energy of the molecules that composes a substance. The atoms and molecules in a substance do not always travel at the same speed. This means that there is a range of energy (the energy of motion) among the molecules. In a gas, for example, the molecules are traveling in random directions at a variety of speeds - some are fast and some are slow. Sometimes these molecules collide with each other. When this happens the higher speed molecule transfers some of its energy to the slower molecule causing the slower molecule to speed up and the faster molecule to slow down. If more energy is put into the system, the average speed of the molecules will increase and more thermal energy or heat will be produced. So, higher temperatures mean a substance has higher average molecular motion. We do not feel or detect a bunch of different temperatures for each molecule which has a different speed. What we measure as the temperature is always related to the average speed of the molecules in a system
Answer:
Electrons.
Explanation:
Electricity was discovered before the discovery of electrons by J.J Thompson in 1896. Before the electron, it was thought that it is the positive ions that move through the wire and carry current—that's why today the conventional current represents the flow of positive charges.
After J.J Thompson's discovery of the electrons, it was realized that it is the electrons that actually carry the current through the conductor. But changing the direction of the conventional current didn't seem appropriate, and that's why the convention continues to be used to this day—reminding us that once it were the positive ions that were thought to carry the current.
Answer:
Explanation:
Since the block is at rest in an elevated position, we can assume that it only has potential energy.
U=mgh is the formula for potential energy where U=potential energy, m= mass, g=acceleration due to gravity, and h=height.
Plug in known variables....
U=4kg*9.8m/s^2*20m
U=784 joules of potential energy or letter A.
