Answer:
Explanation:
On both sides of the film , the mediums have lower refractive index.
for interfering pattern from above , for constructive interference of reflected wave from both sides of the film , the condition is
2μt = ( 2n +1 ) λ / 2
μ is refractive index of film ,t is thickness of film λ is wavelength of light
n is order of fringe
for minimum thickness
n = 0
2μt = λ / 2
t = λ / 4μ
= 670 / 1.75 x 4
= 95.71 nm .
Explanation:
When you observe the night sky you will notice that the stars are moving. They rise from eastern horizon and set in the western horizon. It happens due to rotation of Earth. When observed closely you will notice that the all the stars seem to go around the pole star. Out of all the stars there are some stars which neither set not rise, such stars are called as Circumpolar stars. This means that they are always above the horizon. If we trace the path of such stars they will appear to make complete circle around the pole star.
Also, you will notice that the altitude of pole star (separation of pole star from the horizon in degrees) will depend on the location of observe on the Earth. This happens due to Earth being spherical. So if you are on equator the pole star will be on the horizon i.e. 0° altitude. If you are at Poles, altitude of the pole star will be 90°. Technically the altitude of pole star at any place on Earth is equal to the latitude of the place.
If the altitude of pole star varies and increases as you move towards higher latitude on Earth, the distance between horizon and pole star will also increase. This will result in more stars being circumpolar.
If you are at Poles, all the stars will be circumpolar and if you are at equator no star will be circumpolar.
Answer : Use a magnet to pull out the iron filings as they are attracted to a magnet
Explanation : we use the magnet to separate the sand from the iron filing. Because the magnet has an attraction power.
We can say that we can use the magnet to attract the iron filings out of the mixture because iron is magnetic solid, but sand will not attract because sand is not magnetic solid.
So, we use a magnet to pull out the iron filings as they are attracted to a magnet.
Answer:
The answer is A
Explanation:
Lightning is formed by electrons in the air
