Answer: The hottest star is Archenar( blue) and the coolest star is Betelgeuse
Explanation:
Objects emit radiation that depends exclusively on their temperature. At an ambient temperature, the radiation emitted by an object is in the infrared spectrum (we could only see it with a special camera). If we heat it we will see that it first turns red (whose state we call “red hot”) because it is the lowest and least energetic wavelength of all.
If we continue to heat it, the wavelength that it emits to one with more energy will continue to increase and we will see that it turns yellow and then white. This is a signal that is emitting at all frequencies (but mainly in blue).
If we continue to warm a body that is "white hot", it would emit in the ultraviolet spectrum, with what would become ... black! then we would not see it emits light in the visible spectrum (well, we would see a very faint bluish light corresponding to the tail of the distribution of the spectrum it emits, but the peak of that spectrum would be in the ultraviolet).
It would be Thermal Radiation
Explanation:
Given that,
Rate of cooling of air
Initial temperature= 80°C
Final temperature = 5°C
We need to calculate
Using newton's law of cooling
Where, 
Here, 
= 25°C (surrounding temperature)
dt = 1 minute
Put the value into the formula
Hence, This is the required answer.
Answer:
d ) is the answer.
Explanation:
Let M be the mass and R be the radius of each of ball , hoop and disc.
kinetic energy of sphere - 1/2 MV² + 1/2 I ω² ,ω is angular velocity and
V = ωR
kinetic energy of sphere - 1/2 MV² + 1/2 x 2/5 MR² ω²
= 1/2 MV² + 1/5 MR² ω²
MV² ( 1/2 + 1/5 )
= .7 MV²
kinetic energy of Disk - 1/2 MV² + 1/2 I ω² ,ω is angular velocity and
V = ωR
kinetic energy of Disk - 1/2 MV² + 1/2 x 1/2 MR² ω²
= 1/2 MV² + 1/4 MR² ω²
MV² ( 1/2 + 1/4 )
= .75 MV²
kinetic energy of Hoop - 1/2 MV² + 1/2 I ω² ,ω is angular velocity and
V = ωR
kinetic energy of hoop - 1/2 MV² + 1/2 MR² ω²
= 1/2 MV² + 1/2 MR² ω²
MV² ( 1/2 + 1/2 )
= MV²
Kinetic energy is largest in case of hoop and least in case of sphere . So hoop will go up to the highest point and sphere will go to a height which will be least among the three.
Answer:
-3044.848m/s^2
Explanation:
Initial velocity = 15.7 m/s (u)
Final velocity = -14.444 m/s (v) velocity after striking moving opposite direction.
Time = 0.0099 s
Average acceleration :
change in velocity/ total time
= V - U/t
= -14.444 m/s - 15.7 m/s/0.0099 s
= -30.144/0.0099 s
= -3044.848m/s^2
