The correct answer for the question that is being presented above is this one: "Schmidt-Cassegrain focus." A focal arrangement that has a thin lens that the light passes through before traveling down the tube to the objective mirror is a Schmidt-Cassegrain focus.
Here are the following choices:
a. Cassegrain focus
b. Newtonian focus
c. Schmidt-Cassegrain focus
<span>d. Schmidt focus</span>
Answer:
the decay of half of the nuclei only a half-life has passed
, b) in rock time it is 1 108 years
Explanation:
The radioactive decay is given by
N = N₀
If half of the atoms have decayed
½ N₀ = N₀
½ =
₀
Ln 0.5 = - λ t
t = - ln 0.5 /λ
The definition of average life time is
= ln 2 / λ
λ = ln 2 / 
λ = 0.693 / 100 10⁶
λ = 0.693 10⁻⁸ years
We replace
t = -ln 0.5 / 0.693 10⁻⁸
t = 10⁸ years
We see that for the decay of half of the nuclei only a half-life has passed
b) in rock time it is 1 108 years
Answer: Can I get a picture???
Stars are made of very hot gas. This gas is mostly hydrogen and helium, which are the two lightest elements. Stars shine by burning hydrogen into helium in their cores, and later in their lives create heavier elements.
Answer
The intensity of a sound wave depends on the pressure of the wave,density of the medium and speed of sound in the medium. Higher density and higher sound speed both give a lower intensity. and may be it is because that sound wave is more characterize by wavelength than frequency..explanation
Explanation:
As decibel levels get higher, sound waves have greater intensity and sounds are louder. For every 10-decibel increase in the intensity of sound, loudness is 10 times greater. Intensity of sound results from two factors: the amplitude of the sound waves and how far they have traveled from the source of the sound.