The phase difference between the electric and magnetic fields in an electromagnetic wave is

Which statement correctly explains how the Hertzsprung-Russell diagram helps to compare stars?

tekilochka [14]

Answer:

The Hertzsprung-Russell diagram plots stars according to their luminosity and temperature, which is also associated with spectral class.

Explanation:

The Hertzsprung-Russell is a diagram representing:

- The surface temperature of the stars on the x-axis

- The absolute luminosity of the stars on the y-axis

So, the H-R diagram shows the relationship between the luminosity (power output) of a star and its temperature.

Most of the stars in the diagram are located along a diagonal line going from the top left to the bottom right: the stars in this diagonal are the stars in the main sequence, which is the main phase of life of a star.

Also, the graph shows that for stars in the main sequence, as the temperature increases, the luminosity also increases: these are the blue supergiant stars located in the top left corner.

Then, apart from the main sequence line, there are other groups of stars located in the top right corner (red giants) and in the bottom left corner (red, white dwarfs).

So, the correct answer is

The Hertzsprung-Russell diagram plots stars according to their luminosity and temperature, which is also associated with spectral class.

4 0

4 years ago

A solar sail allows a spacecraft to use radiation pressure for propulsion, similar to the way wind propels a sailboat. The sails

Neporo4naja [7]

Answer:

F = 2 I A / c

Explanation:

The radiation pressure on a reflective surface is

P = 2 S / c

Where S is the Poynting Vector and c the speed of light

Furthermore pressure is defined as the ratio of force to area

P = F / A

Let's replace

F / A = 2 S / c

F = 2 S A / c

The poynting vector is the power per unit area that is equal to the intensity

S = I

F = 2 I A / c

7 0

3 years ago

ou are walking down a straight path in a park and notice there is another person walking some distance ahead of you. The distanc

alexgriva [62]

Answer:

The value is $d = 31.45 \ m$

Explanation:

Generally the relative speed at which you are moving with respect to the person ahead of you is mathematically represented as

$v_r = v_s - v_c$

substituting 1.05 m/s for $v_c$ and 2.75 m/s for $v_s$

So

$v_r = 2.75 - 1.05$

=> $v_r = 1.7 \ m/s$

Generally the distance by which the person is ahead of you is mathematically represented as

$d = v_r * t$

substituting 18.5 s for $t$

$d = 1.7 * 18.5$

=> $d = 31.45 \ m$

4 0

3 years ago

Ground-based radio telescopes can collect data from distant objects in space

Butoxors [25]

Answer:

A. during the day or night and in any weather conditions.

Explanation:

Ground-based radio telescopes can be used to collect data from distant objects in space during the day or night in any weather condition.

They do not depend or are they affected by weather and they pass well through them.

Telescopes are devices used to obtain information about distant bodies usually astronomical in nature.
Optical telescopes use the visible range of light and they are overwhelmed by the sun during the day.
Bad weather conditions can also diminish the reception of light.
They work best at night.
Radio telescopes uses electromagnetic radiations and can work at any time and during any weather.

6 0

3 years ago

An image of a car with height of 14 cm occurred in the mirror which is located at a T-

Thepotemich [5.8K]

Answer:

The distance of car form the mirror is 330 cm.

Explanation:

height of object, h = 140 cm

height of image, h' = 14 cm

radius of curvature, R = 60 cm

focal length, f = R/2 = + 30 cm

Let the distance of image is v and the distance of object is u.

$\frac{h'}{h}\frac{v}{u}\\\\\frac{14}{140} =\frac{v}{u}\\\\v =\frac{u}{10}$

Use the formula of focal length

$\frac{1}{f}=\frac{1}{v}+\frac{1}{u}\\\\\frac{1}{30}=\frac{10}{u}+\frac{1}{u}\\\\\frac{1}{30}=\frac{11}{u}\\\\u = 330 cm$

3 0

3 years ago