Explanation:
average speed = total distance travelled / total time travelled
time to travel the first 6km: 6 / 50 = 3/25 (h)
time to travel the next 6km: 6 / 90 = 1/15 (h)
[I think there's problem in the question 'cause 900km/h sounds impossible for normal person to travel in normal condition]
The total time: 3/25 + 1/15 = 14/75 (h)
Average speed over the 12 km drive will be:

All frequencies of light in hertz are in between

and

Light with a lower frequency than 4 * 10^14 Hz, are called infrared and can't be seen by human eye. Light with a higher frequency than 8 * 10^14 Hz, are called ultraviolet and can't bee seen by human eye.
Therefore, the maximum frequency of visible light in Hz, is
8 * 10^14 Hz
Answer:
λ = V / f the wavelength versus the frequency
V = f λ and V (speed) proportional λ for a fixed frequency
F = f^2 * (M / L) * λ^2 = (f * λ)^2 * (M / L)^2 force (tension) on string at a given frequency
F2 / F1 = (λ2 / λ1)^2 other items are constant
Let λ1 = 6 then λ2 must be 3/2 λ1 for a constant length
F2 / F1 = (6 / 4)^2 = 9/4
The tension must be increased to 9 / 4 of the original tension
Check: if the frequency is fixed then V will be larger for a larger wavelength (situation 2)
One can also write V = (F / (M / L))^1/2
Then for fixed M L
F2 / F1 = (V2 / V1)^2
Since V = f λ Velocity is proportional to λ for a fixed frequency
Then if V2 / V1 = 3 / 2 F2 = 9/4 F1
Answer:a) λ = 4.862 10⁻⁷ m, b) λ = 4.341 10⁻⁷ m
Explanation:
The spectrum of hydrogen can be described by the expression
in the case of the initial state n = 2 this series is the Balmer series
a) Find the wavelength for n = 4
let's calculate
= 1,097 10⁷ ()
\frac{1}{ \lambda} = 1.097 10⁷ 0.1875 = 0.2056 10⁷
λ = 4.862 10⁻⁷ m
b) n = 5
\frac{1}{ \lambda} = 1,097 10⁷ ()
\frac{1}{ \lambda} = 1.097 10⁷ 0.21 = 0.23037 10⁷
λ = 4.341 10⁻⁷ m
Answer:
the conversion of matter into energy
Explanation:
A nuclear reaction is a reaction in which there is a change in the nuclei of the atoms involved. The two most important examples of nuclear reactions are:
- Nuclear fission: it occurs when a heavy, unstable nucleus breaks apart into two or more lighter nuclei
- Nuclear fusion: it occurs when two lighter nuclei fuse together into a heavier nucleus
In both cases, the total mass of the final products is smaller than the total mass of the initial nuclei: this means that part of the mass of the initial nuclei has been converted into energy, according to Einstein's formula:

where
is the variation of mass and c is the speed of light. Since the value of c is very large, we can see from the formula that even a small amount of
is able to produce a huge amount of energy, and this is a typical feature of any nuclear reaction.