Answer:
D. Test a piece of treated iron and a piece of untreated iron under the same conditions.
Explanation:
A controlled experiment is defined as an experiment where the experimenter or the researcher tries to test or experiment his result by changing one variable at a time and keeping the other factors under the same conditions and sees how it effects the result.
The factors which can be changed in an experiment is called its variables.
In the context, testing a piece of treated iron as well as a untreated piece of iron under the same working conditions forms a controlled experiment.
Answer:
C. 1.15
Explanation:
The formula for the critical angle is:
Where,
is the critical angle
is the refractive index of the refractive medium. ( Alcohol , ? )
is the refractive index of the incident medium. ( Glass, 1.66 )
<u>Critical angle = 44º</u>
Applying in the formula as:
The Energy flux from Star B is 16 times of the energy flux from Star A.
We have Two stars - A and B with 4900 k and 9900 k surface temperatures.
We have to determine how many times larger is the energy flux from Star B compared to the energy flux from Star A.
<h3>State Stephen's Law?</h3>
Stephens law states that if E is the energy radiated away from the star in the form of electromagnetic radiation, T is the surface temperature of the star, and σ is a constant known as the Stephan-Boltzmann constant then-
Now -
Energy emitted per unit surface area of Star is called Energy flux. Let us denote it by E. Then -
Now -
For Star A →
= 4900 K
For Star B →
= 9900 K
Therefore -
2.02 = 2 (Approx.)
Now -
Assume that the energy flux of Star A is E(A) and that of Star B is E(B). Then -
E(B) = E(A) x 
E(B) = E(A) x 
E(B) = 16 E(A)
Hence, the Energy flux from Star B is 16 times of the energy flux from Star A.
To learn more about Stars, visit the link below-
brainly.com/question/13451162
#SPJ4
Answer: B. the isovolumetric process
Explanation:
In the graph given, the volume is constant throughout. It represents a constant volume process. Such processes are called the isovolumetric process or isochoric process.
<em>Hence, option B is the correct answer.</em>
Option A is incorrect because in an isobaric process, the pressure is constant.
Option C is incorrect because in an isothermal process, the temperature is constant.
Option D is incorrect because in an adiabatic process there is no heat transfer.
When storm clouds produce lightening and thunder, then, potential energy changes into kinectic energy.
The clouds become negatively charged,and the ground is positively charged during a storm. So there creates a potential difference between the charged clouds and the ground. And when this becomes huge so much that it over comes the electrical insulation cover of air, the electrons jump to the ground.i.e. the potential energy changes into kinetic energy.
