Explanation:
The lines in the spectra of star is due to absorption of light emitted by star by different elements present in atmosphere of the star .
If some element is present in the outer atmosphere of he star , it will absorb a particular portion of light , for which there will be black line in the spectrum .
These are called Fraunhoffer's lines .
Now there is no such line at the place of Helium in the light spectrum . This means that Helium element is not present in the outer atmosphere of the star.
Answer:
Explanation:
The amplitude of he combined wave is:
A, is the amplitude from the identical harmonic waves
B, is the amplitude of the resultant wave
θ, is the phase, between the waves
The amplitude of the combined wave must be 0.6A:
Answer:
The particle’s velocity is -16.9 m/s.
Explanation:
Given that,
Initial velocity of particle in negative x direction= 4.91 m/s
Time = 12.9 s
Final velocity of particle in positive x direction= 7.12 m/s
Before 12.4 sec,
Velocity of particle in negative x direction= 5.32 m/s
We need to calculate the acceleration
Using equation of motion
Where, v = final velocity
u = initial velocity
t = time
Put the value into the equation
We need to calculate the initial speed of the particle
Using equation of motion again
Put the value into the formula
Hence, The particle’s velocity is -16.9 m/s.
Answer:
128.21 m
Explanation:
The following data were obtained from the question:
Initial temperature (θ₁) = 4 °C
Final temperature (θ₂) = 43 °C
Change in length (ΔL) = 8.5 cm
Coefficient of linear expansion (α) = 17×10¯⁶ K¯¹)
Original length (L₁) =.?
The original length can be obtained as follow:
α = ΔL / L₁(θ₂ – θ₁)
17×10¯⁶ = 8.5 / L₁(43 – 4)
17×10¯⁶ = 8.5 / L₁(39)
17×10¯⁶ = 8.5 / 39L₁
Cross multiply
17×10¯⁶ × 39L₁ = 8.5
6.63×10¯⁴ L₁ = 8.5
Divide both side by 6.63×10¯⁴
L₁ = 8.5 / 6.63×10¯⁴
L₁ = 12820.51 cm
Finally, we shall convert 12820.51 cm to metre (m). This can be obtained as follow:
100 cm = 1 m
Therefore,
12820.51 cm = 12820.51 cm × 1 m / 100 cm
12820.51 cm = 128.21 m
Thus, the original length of the wire is 128.21 m
Answer: I think its 120
Explanation: thx for the free points :)
