Answer:
t = 94.91 nm
Explanation:
given,
wavelength of the light = 522 nm
refractive index of the material = 1.375
we know the equation
c = ν λ
where ν is the frequency of the wave
c is the speed of light
ν = 5.75 x 10¹⁴ Hz
the thickness of the coating will be calculated using
t = 94.91 nm
the thickness of the coating will be equal to t = 94.91 nm
Answer:
The frequency of the phonograph record is 0.2 Hz
Explanation:
The frequency of an object moving in uniform circular motion is the number of completed cycles the object makes in a specified time period
The given parameters of the phonograph record are;
The radius of the record = 0.15 m
The number of times the phonograph record rotates, n = 18 times
The time it takes the phonograph record to rotate the 18 times, t = 90 seconds
The frequency of the phonograph record, f = (The number of times the phonograph record rotates) ÷ (The time it takes the phonograph record to rotate the 18 times)
∴ The frequency of the phonograph record, f = n/t = 18/(90 s) = 0.2 Hz
The frequency of the phonograph record = 0.2 Hz.
Answer: Carbon 14 and Uranium 238 are not used together to determine fossil ages.
Explanation:
Carbon 14 with a half life of 5,700 years can only be used to date fossils of approximately 50,000 years. Most fossils are thought to be much older than 50,000 years. Also most fossils no longer contain any Carbon. The fossilized remains have been mineralized where the original organic material has been replaced and turned into stones containing no carbon.
Uranium 238 has a half life of 4.5 billion years. Uranium can be used to date the age of the earth. If 50% of pure uranium' is left in a sample the sample is assumed to be 4.5 billion years old.( This is assuming that the original sample was 100% uranium and no Uranium 238 has been eroded or lost in 4.5 billion years old. If a fossil has only 25 % of the Uranium 238 the sample has an estimated age of 3.2 Billion years. This would be the estimated age of the earliest life or formation of fossils.
Note no fossils contain Uranium 238. Uranium 238 is only found in igneous or volcanic rocks. So no fossils can be dated directly using U 238.
Because of the huge differences in the half lives of Carbon 14 and Uranium238 they cannot be used together. Carbon 14 can only be used to date fossils of a very recent age. Uranium 238 can only be used to date volcanic rocks of a very old age.
Answer:
the angular velocity of the carousel after the child has started running =
Explanation:
Given that
the mass of the child = m
The radius of the disc = R
moment of inertia I = 
change in time = 
By using the torque around the inertia ; we have:
T = I×∝
where
R×F = I × ∝
R×F = ∝
F = 
∝
∝ = 
( expression for angular angular acceleration)
The first equation of motion of rotating wheel can be expressed as :
where ;
∝ =
Then;
∴ the angular velocity of the carousel after the child has started running =
