Answer:
Period of brightness variation and luminosity.
Explanation:
The Cepheid variables are used as distance indicators. This requires estimation of periods and (usually) intensity-mean magnitudes in order to establish a period—apparent luminosity relation. It is particularly important for the techniques employed to be as accurate and efficient as possible.
Answer:
Explanation:
Given
speed of Electron 
final speed of Electron 
distance traveled 
using equation of motion

where v=Final velocity
u=initial velocity
a=acceleration
s=displacement


acceleration is given by 
where q=charge of electron
m=mass of electron
E=electric Field strength

The imbalance of electric charges within or on the surface of a material or between materials is known as static electricity. When you grab a doorknob, electrons jump from your hand to the knob .which conducts electricity, giving you a shock.
<h3>What is static electricity?</h3>
The imbalance of electric charges within or on the surface of a material or between materials is known as static electricity.
The charge will persist until it can be moved away by an electric current or an electrical discharge.
when we walk on the carpet with socks our feet slide electrons off the carpet. it leads to leaving you with a slightly negative static charge.
When you grab a doorknob electrons jump from your hand to the knob which conducts electricity giving you a shock.
Due to the static electricity jump from your hand to the knob .which conducts electricity giving you a shock.
To know more about static electricity refer to the link ;
brainly.com/question/821085
Option B is the correct answer that show how magnetic field lines should be drawn for the magnets shown in the figure.
<h3>
What is Magnetic Line of Force ?</h3>
The Magnetic Line of Force of a magnet is defined as the line along which a free N - pole would tend to move if placed in the field of a line such that the tangent to it at any point gives the direction of the field at that point.
When the two unlike poles are placed to each other, there will be attraction. And when the two like poles are placed to each other, there will be repulsion. The reason is that the line of force tend to move from the north pole to the south pole.
From the given diagram, the two magnets are of the same south pole. They are of like pole and there will be repulsion between the two magnets.
Therefore, Option B is the correct answer that show how magnetic field lines should be drawn for the magnets shown in the figure.
Learn more about Magnetic Field Lines here: brainly.com/question/17011493
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The
resulting vector is the sum of the T + U + V vectors component to component.
Therefore, if you want to find the x component of the resulting vector, the
correct formula is:
<span>Tx + Ux + Vx</span>