Answer : The value of 
is 286.2 J and 286.2 J respectively.
Explanation : Given,
Moles of sample = 0.877 mol
Change in temperature = 15.7 K
First we have to calculate the heat absorbed by the system.
Formula used :
where,
q = heat absorbed by the system = ?
n = moles of sample = 0.877 mol
= Change in temperature = 15.7 K
= heat capacity at constant volume of 
(diatomic molecule) = 
R = gas constant = 8.314 J/mol.K
Now put all the given value in the above formula, we get:
Now we have to calculate the change in internal energy of the system.
As we know that, work done is zero at constant volume. So,
Therefore, the value of is 286.2 J and 286.2 J respectively.
As the number of significant figures increases, the more accurate or precise the measurement is.
<h3>What is significant figure?</h3>
The term significant figures refers to the number of important single digits in the coefficient of an expression in scientific notation.
Significant figures are the digits in a value that are known with some degree of confidence.
The effect of reporting more or fewer figures or digits than are significant;
As the number of significant figures increases, the more accurate or precise the measurement is.
As precision of a measurement increases, so does the number of significant figures.
Learn more about significant figures here: brainly.com/question/24491627
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Answer:
n = 4 x 10¹⁸ photons
Explanation:
First, we will calculate the energy of one photon in the radiation:
where,
E = Energy of one photon = ?
h = Plank's Constant = 6.625 x 10⁻³⁴ J.s
c = speed of light = 3 x 10⁸ m/s
λ = wavelength of radiation = 567 nm = 5.67 x 10⁻⁷ m
Therefore,
E = 3.505 x 10⁻¹⁹ J
Now, the number of photons to make up the total energy can be calculated as follows:
<u>n = 4 x 10¹⁸ photons</u>
The two points on a periodic wave in a medium are said to be in phase if they have the same amplitude and are moving in the same direction.
Option 4.
Explanation:
A periodic wave is termed for waves which flow in a repetition pattern in a given time scale. Periodic wave can also be termed as a transverse wave. So a transverse wave have various crests and troughs. The two successive crests and two successive troughs are said to be in phase with each other.
Thus, for a periodic wave in a medium, the in phase can be obtained in two points which have the same amplitude and are moving in the same direction.
As amplitude is a scalar quantity and so direction should be taken into consideration for making the points related to successive crests only in phase with themselves. Also this also relates the points related to successive troughs to be in phase with each other. But a crest and a trough will not be in phase with each other.
Thus, option 4, that is the two points on a periodic wave in a medium are said to be in phase if they have the same amplitude and are moving in the same direction.
