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
jok3333 [9.3K]
3 years ago
14

A) Show that the surface temperature of a star can be inferred from measurements of blackbodyfluxes at two different frequencies

, even if the stellar radius and distance are unknown.
b) Explain why in practice this method does not work well if both frequencies are on theRayleigh-Jeans side of the spectrum,hνkT.
c) Derive a simple, approximate expression for the temperature when both measurements areon the Wien tail,hνkT.
d) Derive an expression for the star’s radius if a distance measurement is also available (e.g.,from parallax).

Physics
1 answer:
Roman55 [17]3 years ago
3 0

Answer:

The answers to the questions have been solved in the attachment.

Explanation:

The answers to part a to e are all contained in the attachment. For answer part b, temperature and frequency were assumed to be fixed or constant. V² is directly proportional to T telling us that variation in T gives us a square in the frequency variation. This tells us why it is difficult when both frequencies are on this side of the black body.

You might be interested in
I need help in my physics class and show me how it’s done
Korolek [52]

If we have the angle and magnitude of a vector A we can find its Cartesian components using the following formula

A_x = |A|cos(\alpha)\\\\A_y = |A|sin(\alpha)

Where | A | is the magnitude of the vector and \alpha is the angle that it forms with the x axis in the opposite direction to the hands of the clock.

In this problem we know the value of Ax and Ay and we need the angle \alpha.

Vector A is in the 4th quadrant

So:

A_x = 6\\\\A_y = -6.5

So:

|A| = \sqrt{6^2 + (-6.5)^2}\\\\|A| = 8.846

So:

Ay = -6.5 = 8.846cos(\alpha)\\\\sin(\alpha) = \frac{-6.5}{8.846}\\\\sin(\alpha) = -0.7348\\\\\alpha = sin^{- 1}(- 0.7348)

\alpha = -47.28 ° +360° = 313 °

\alpha = 313 °

Option 4.

4 0
3 years ago
A system gains 757 kJ757 kJ of heat, resulting in a change in internal energy of the system equal to +176 kJ.+176 kJ. How much w
Alecsey [184]

Answer:

581 kJ, work was done by the system

Explanation:

According to the first law of thermodynamics:

\Delta U = Q-W

where

\Delta U is the change in internal energy of the system

Q is the heat absorbed by the system (positive if absorbed, negative if released)

W is the work done by the system (positive if done by the system, negative if done by the surrounding)

In this problem,

Q=+757 kJ

\Delta U = +176 kJ

Therefore the work done by the system is

W=Q-\Delta U=757 kJ-176 kJ=+581 kJ

And the positive sign means the work is done BY the system.

5 0
3 years ago
True or False—An external force is defined as a force generated outside the system of interest that acts on an object inside the
inn [45]

Answer:

An external force is a force that acts on an object within the system from outside the system. This type of force is different than an internal force, which acts between two objects that are both within the system. The net external force combines these two definitions; it is the total combined external force

Explanation:

ig the answer is true

5 0
3 years ago
I NEED HELP WITH THE LAST QUESTION I’L MARK U AS BRANLIEST
velikii [3]

Answer:

gap junctions,tight junctions,and desmosomes

6 0
3 years ago
A book has been lifted 1.5 meters into the air giving it 30J of potential energy. How much force was used to lift it
joja [24]

Answer:

Force on the object is 20 N

Explanation:

As we know that work done to raise the book from initial position to final position is known as potential energy stored in it

So here we know that

U = F.s

here we know that

U = 30 J

s = displacement = 1.5 m

so we have

30 = F(1.5)

F = 20 N

6 0
3 years ago
Other questions:
  • Which is heavier—warm air or cold air?
    15·1 answer
  • Emmett is lifting a box vertically. Which forces are necessary for calculating the total force?
    15·1 answer
  • For what type of power tool is it especially important to take precautions to prevent a tool component from coming loose and fly
    11·1 answer
  • The slope of the line on a speed-time graph tells the speed.
    10·1 answer
  • A light bulb is left on for an hour and has a power of 0.1KW. How much did it cost?
    12·1 answer
  • A toy car that 0.12 m long is used to model the actions of an actual car that is 6m long. Which ratio shows the relationship bet
    12·1 answer
  • a vertical solid steel post 29cm in diameter and 2.0m long is required to support a load of 8200kg, ignore the weight of the pos
    5·1 answer
  • If i died would i die?
    15·2 answers
  • When a central force acts upon an object with a mass of 8kg, the acceleration of the object is 7m/s^2. When the same force acts
    9·1 answer
  • Suppose the position of a particle moving along the x-axis given by the equation X=(1m/s²)t²-(5m/s)t +0.5m
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!