I think your question should be:
An industrial laser is used to burn a hole through a piece of metal. The average intensity of the light is
What is the rms value of (a) the electric field and
(b) the magnetic field in the electromagnetic wave emitted by the laser
Answer:
a)
b)
Explanation:
To find the RMS value of the electric field, let's use the formula:
Where
;
;
Therefore
b) to find the magnetic field in the electromagnetic wave emitted by the laser we use:
;
;
Carbon-13 will have 6 protons (because it is carbon), 6 electrons, and 7 neutrons. Isotopes have a different number of neutrons.
Answer: 0.2N
Explanation:
mass of wagon = 100 grams
Convert mass in grams to kilograms
If 1000 grams = 1kg
100 grams = (100/1000) = 0.1kg
Acceleration of wagon = 2m/s/s
Force on the wagon = ?
Recall that Force is the product of mass of an object by the acceleration by which it moves.
i.e Force = mass x acceleration
Force = 0.1kg x 2m/s/s
Force = 0.2N
Thus, the force on the wagon is 0.2Newton
1. Mass number of Lithium-7: 7
Explanation:
- The atomic number of an element is equal to the number of protons inside its nucleus
- The mass number of an element is equal to the number of protons+neutrons inside its nucleus
The nomenclature "Element-X", where X is the number of protons+neutrons, is used to indicate the mass number of the isotope. Therefore, an isotope of LIthium-7 has a mass number of 7.
2. An isotope of lithium-8 contains 5 neutrons
Explanation:
Lithium is the third element of the periodic table, so its atomic number is 3, which means that it has 3 protons.
In this problem, we have an isotope of lithium-8, which means that it has a mass number of 8: so, the sum of neutrons+protons in its nucleus is 8:
where p is the number of protons and n the number of neutrons. However, we also know that for lithium p=3, so we can find the number of neutrons:
"<em>F = dP/dt. </em> The net force acting on an object is equal to the rate at which its momentum changes."
These days, we break up "the rate at which momentum changes" into its units, and then re-combine them in a slightly different way. So the way WE express and use the 2nd law of motion is
"<em>F = m·A.</em> The net force on an object is equal to the product of the object's mass and its acceleration."
The two statements say exactly the same thing. You can take either one and work out the other one from it, just by working with the units.