CHEMISTRY HIGH SCHOOL

What is the minimum total energy released when an electron and its antiparticle (positron) annihilate each other?

Answers

Answer 1
Answer: Energy, in a form of gamma rays, is released when an electron and its antiparticle (positron) annihilate each other. 
Answer 2
Answer:

Solution:

the minimum total energy released when an electron and its antiparticle (positron) annihilate each other is:-

2 mc^2.    [Mass of electron m and c is the velocity of light.]  

m=1*10^(-30) kg., c =3*10^ 8 m/s  

energy released = 2 *9* 10 ^(-14) j  

1 j =6*10^(18) eV.  

Energy released = 6*18*10^4 eV

                               =104*10^4 eV  

                                 =1.04 MeV.



Related Questions

HIGH SCHOOL

Gated ion channels I. exist because active transporters cannot maintain the gradient at a rate equal to non-gated ion flow. II. remain open unless acted on by an external stimulus. III. remain open to all ions that are smaller than the pore diameter. IV. can transport varying ions.

Answers

Answer:

IV. Can transport varying ions.

Explanation:

Gated ion channels intervene in the transit of ions through the cell membrane. The transport through these channels is extremely fast, and they are highly selective since their narrow pores limit the passage to those ions with an appropriate size and charge. This way, specific gated ion channels allow the transit of Na⁺, K⁺, Ca²⁺, and Cl⁻ through the membrane. Also, most of the ion channels are not permanently open, but they open transiently in response to specific stimuli (a ligand or a change in voltage).

MIDDLE SCHOOL

What types of evidence do scientists use to determine evolutionary relationships among groups

Answers

There are several things that can help scientists evaluate which category something belongs to. The similarity in features is one of them. If two skulls looked alike, they were probably species of the same evolutionary category. For example say humans and monkeys rather than humans and dogs.
Similarly fossils have helped scientists categorise species. Study of the chromosomes (in cases with available chromosomes) can help scientists figure out a lot about the subjects and categorise them. 
HIGH SCHOOL

A student used 10 mL water instead of 30mL for the extraction of the NaCl from the mixture. How would this affect the calculated percentage of NaCl in the sample?

Answers

In this problem, the solute is sodium chloride, the salt while the solvent which comprise of a larger mass in the solution is water. When the solvent volume is decreased which is related to its mass, with the solute mass being held constant, then the concentration of salt increases. This is called concentration method. 
MIDDLE SCHOOL

How does the calorie compare to the metric unit the joule? How do you calculate a calorie? Is it the same for all types of food?

Answers

Answer: One calorie is an energy unit of measure equal to about 4.184 joules. As such calorie is a fixed amout of energy and is the same for all types of food.


Explanation:


A calorie is defined as the amount of heat that must supplied to 1 gram of liquid water to increase its temperature 1°C.


The unit calore was established for the metric system, but the current standard SI system of measures use the joule as the the unit for energy.


As said the equivalence between calories and joules is 1 cal = 4.184 joules.


The energy content of the food is usually referred as calories, although it is really kilo calories. For instance, when you say that a snack contains 250 calories, it actually has 250 kilocalories (250,000 calories).


Food calories (the energy content of food) may be measured with a calorimeter, which is the original method. A calorimeter is a device  utilised to burn a sample of food and measure the temperature change in the surrounding water. Although you can use that method in a laboratory, nowadays the energy content is measured indirectly by adding up the energy provided by the energy-containing nutrients (protein, carbohydrates and fats).

Random Questions