1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
MrRa [10]
3 years ago
12

A graduate student has done a careful analysis of the spectrum of a star. While she has found lines from many elements, there wa

s not a trace of the element helium in the spectra she has been analyzing. From this she can now conclude:_______
Physics
1 answer:
disa [49]3 years ago
7 0

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.

You might be interested in
A team of bicyclists are on bikes that require 512 J of work to ride. It takes 432 J of work for the bike to turn the gears. Wha
Alja [10]

Answer:

84.4 %

Explanation:

Mechanical efficiency = output work/input work × 100 %

output work = 432 J of work for the bike to turn the gears

input work = 512 J of work to ride.

Mechanical efficiency =  432 J/512 J × 100 %

= 0.844 × 100%

= 84.4 %

8 0
3 years ago
The vector product of vectors A⃗ and B⃗ has magnitude 12.0 m2 and is in the +z-direction.Vector A⃗ has magnitude 4.0 m and is in
g100num [7]

Answer:

θ=180°

Explanation:

The problem says that the vector product of A and B is in the +z-direction, and that the vector A is in the -x-direction. Since vector B has no x-component, and is perpendicular to the z-axis (as A and B are both perpendicular to their vector product), vector B has to be in the y-axis.

Using the right hand rule for vector product, we can test the two possible cases:

  • If vector B is in the +y-axis, the product AxB should be in the -z-axis. Since it is in the +z-axis, this is not correct.

  • If vector B is in the -y-axis, the product AxB should be in the +z-axis. This is the correct option.

Now, the problem says that the angle θ is measured from the +y-direction to the +z-direction. This means that the -y-direction has an angle of 180° (half turn).

8 0
3 years ago
What is the best free energy source?<br> Nuclear<br> Solar<br> Natural Gas
Free_Kalibri [48]
Solar it is the cheapest and widely used energy source
4 0
3 years ago
Which of the following types of electromagnetic radiation has the longest wavelength? choose one answer.
Setler79 [48]
The right answer is red light
8 0
3 years ago
1. What is the acceleration of a car that goes from 20 Km/hr to 100 km/hr in 8 seconds?
san4es73 [151]

Answer:

10 :)

You have to divide the difference of speed and divide it by the time. So 100-20 would be 80, and if you divide that by 8 it would be 10.

Hope this helps.

7 0
3 years ago
Read 2 more answers
Other questions:
  • In an effort to protect a rhino, volunteers are following its steps with air monitoring and ground cameras. The rhino starts on
    8·1 answer
  • What part of the hammer acts as the fulcrum when the hammer is used to remove a nail
    11·1 answer
  • An electron that has a velocity with x component 1.6 × 106 m/s and y component 2.4 × 106 m/s moves through a uniform magnetic fi
    7·1 answer
  • A lever and fulcrum are used to lift a fallen tree, which has a weight of 480N. if the lever has a mechanical advantage of 5.5,
    5·1 answer
  • A driver in a car traveling at a speed of 21.8 m/s sees a cat 101m away on the road. How long will it take for the car to accele
    7·1 answer
  • Someone help with this table!! 50 points!!!! Please help ASAP!!!!!!
    13·2 answers
  • What would the force be if the separation between the two charges in the top window was adjusted to 8.19 ✕10-11 m? (The animatio
    6·1 answer
  • A star rotates in a circular orbit about the center of its galaxy. The radius of the orbit is 6.9 x 1020 m, and the angular spee
    12·1 answer
  • 2. The length of a day is based on the amount of time that
    9·1 answer
  • How to solve for time given distance and velocity
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!