Answer:
When the air pressure in the throat and outside the body is less than the air pressure in the middle ear, barotrauma occurs.
Explanation:
Ear barotrauma is a medical condition that describes discomfort in the ear which is caused by pressure differences in the inner and outer ear drum.
Usually, the air pressure in the middle ear is the same as the air pressure in the throat and outside the body.
When we swallow, the eustachian tube opens up and air flows out of and into the middle ear, this balances the pressure. But if the eustachian tube is blocked, the air pressure in the throat and outer body become different from the air pressure in the middle ear.
Explanation:
Only few supernova are observed in our galaxy -
Type II supernovae ( i.e. the explosions of the massive stars ) occurred in the Milky Way, and they might be hidden by the intervening dust if they are located in the more distant parts of our Galaxy .
Type Ia supernovae , which need a white dwarf star in the binary star system , are brighter than the type II supernovae , but some of them could also happen in the older parts of Galaxy which are hidden due to the buildup of the dust and gas .
False the North Star never changes it position
Answer:
The artifact is 11,460 years old.
<u>Explanation</u>:
Given that,
The half life of the carbon-14 is 5730 years and we are left with 255 of the sample of wood from an arti-fact.
So it takes 5730 years for the sample to reduce into half
Initially there will be 100% of the sample so
after first 5730 years, the sample reduces into 50% percent
Now the left 50% sample will take another 5730 years to decay into half of its amount.
after next 5730 years the sample reduces into 25% percent
So totally after 2 half-life the sample reduces into 25%
That is (5730 +5730) years = 11460 years
Answer:
18.89cm
Explanation:
As we know that the person is standing 5m in front of the camera
The focal length of the lens =50cm
f=50 cm
By Lens formula we have:
By the formula of magnification
The height of the image formed is 18.89cm.
