Answer: From space/ astronauts
Explanation:
A black hole is a place in space where gravity pulls so much that even light can not get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying.
Because no light can get out, people can't see black holes. They are invisible. Space telescopes with special tools can help find black holes. The special tools can see how stars that are very close to black holes act differently than other stars.
Answer:
The inducerd emf is 1.08 V
Solution:
As per the question:
Altitude of the satellite, H = 400 km
Length of the antenna, l = 1.76 m
Magnetic field, B = 
Now,
When a conducting rod moves in a uniform magnetic field linearly with velocity, v, then the potential difference due to its motion is given by:
Here, velocity v is perpendicular to the rod
Thus
e = lvB (1)
For the orbital velocity of the satellite at an altitude, H:
where
G = Gravitational constant
= mass of earth
= radius of earth
Using this value value in eqn (1):
Answer:
Option B) This minimizes the harmful side effects of the radiations
Explanation:
Half-life is the time taken for the decay of an radio-active atom in which it disintegrates such that it becomes half of its value at the beginning.... The nuclei should be in active mode for a longer duration sufficient for the treatment of the condition but these nuclei should have a sufficient shorter half life so that they don't get enough time to cause any damage to the health of the person other than treating the cause.
A shorter half life gives the assurance that the radiation after the treatment will leave the body without getting accumulated and cause harm to the body cells and other organs.
·The acceleration of gravity is proportional to
1 / (the square of the distance from the center) .
When we're on the surface, we're 1 radius from the center of the Earth,
and the acceleration of gravity is 9.8 m/s² .
The boy's weight = (mass) · (gravity) = (50kg) · (9.8 m/s²)
= 490 newtons .
At the distance of 5 radii from the center (4 radii altitude from the surface),
the acceleration of gravity is
(9.8 m/s²) · (1/5)² = 0.39 m/s² .
The boy's weight is (mass) · (gravity) = (50kg) · (0.39 m/s²)
= 19.6 newtons .
Just as we expected, his weight at that distance is
(19.6 / 490) = 0.04 = 1/25 = 1/5² of his weight on the surface.
