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4 years ago

When is a white dwarf formed?

1 answer:

4 0

If a red giant has insufficient mass to generate the core temperatures, around 1 billion Kay, required to fuse carbon, and inert mass of carbon and oxygen will build up at its center. After such a star sheds its outer layers and forms a planetary nebula, it will leave behind a core, which is the remnant white dwarf.

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A. Telephone signals are often transmitted over long distances by microwaves. What is the frequency of microwave radiation with

zzz [600]

(a) 10 GHz is the frequency of microwave radiation.

(b) 0.167 ms is required by the microwave to travel between two mountains.

Answer:

Explanation:

(a). 1 MHz is the frequency of microwave radiation.

(b) 0.167 ms is required by the microwave to travel between two mountains.

Answer:

Explanation:

a. Frequency is the measure of number of times a same thing will be repeated in a given time interval for a given time. And wavelength is the measure of distance between two successive crests or troughs. So wavelength and frequency are inversely proportional to each other. And velocity of light is the proportionality constant.

So frequency of microwave radiation = Speed of light/Wavelength of radiation

Frequency = $\frac{3*10^{8} }{3*10^{-2} }$

Frequency = $10^{8+2} = 10^{10}=10 GHz$

So 10 GHz is the frequency of microwave radiation.

b). As microwave is a part of light waves, so it will be experiencing the speed of light.

As the speed is 3* $10^{8}$ m/s and the distance between the two mountains is given as 50 km, then time can be calculated as

Time = Distance/Velocity

Time = $\frac{50*10^{3} m}{3*10^{8} }=16.67*10^{3-8}=16.67*10^{-5}$

So time = 0.167 ms.

Thus, 0.167 ms is required by the microwave to travel between two mountains.

6 0

4 years ago

Jasper made a list of the properties of electromagnetic waves. Identify the mistake in the list. Electromagnetic Wave Properties

Nata [24]

Answer:

Statement 2 is wrong

Explanation:

To check the statements in this exercise, let's describe the main properties of electromagnetic waves. Let's describe the characteristics

* they are transverse waves

* formed by the oscillations of the electric and magnetic fields

* the speed of the wave is the speed of light

with these concepts let's review the final statements

1) True. Formed by the oscillation of the two fields

2) False. They are transverse waves

3) True. Can travel by vacuum as they are supported by oscillations of the electric and magnetic fields

4) True. They all have the same speed of light

Statement 2 is wrong

6 0

4 years ago

Which kinds of objects emit visible light in the electromagnetic spectrum?

Triss [41]

Answer : Relatively hot objects

Explanation : We know that, the temperature of the objects is inversely proportional to their wavelengths. The objects emitting radiation in the visible region have short wavelength and hence are relatively hotter.

We know the range of wavelength of the visible spectrum is from 400 nm to 780 nm.

3 0

3 years ago

Read 2 more answers

One jet is flying east at 880 km/h,and another is traveling north at 880 km/h.Do they have the same velocity?the same speed?Expl

shusha [124]

Velocity is the speed and direction combined.
So, the two jets both are going at the same speed.
But they are going in different directions, so their velocities are different.

6 0

3 years ago

WILL GIVE BRAINLIEST TO CORRECT ANSWER PLEASE HELP ME

koban [17]

Answer:

The total distance is 381.5 [m]

Explanation:

In order to solve this problem we must use the expressions of kinematics. The clue to solve this problem is that the motorcyclist starts from rest, i.e. its initial speed is zero.

$v_{f} =v_{o} +(a*t)$

where:

Vf = final velocity [m/s]

Vo = initial velocity = 0

a = acceleration = 2 [m/s²]

t = time = 7 [s]

Vf = 0 + (2*7)

Vf = 14 [m/s]

With this velocity, we can calculate the displacement using the following expression.

$v_{f} ^{2} =v_{o} ^{2} +2*a*x$

where

x = distance traveled [m]

14² = 0 + (2*7*x)

x = 196/(14)

x = 14 [m]

Note: The positive sign in the equations is because the car is accelerating, it means its velocity is increasing.

The other important clue to solve this problem in the second part is that the final velocity is now the initial velocity.

We must calculate the final velocity.

$v_{f}= v_{i} +(a*t)$

Vf = final velocity [m/s]

Vi = initial velocity = 14 [m/s]

a = desacceleration = 4 [m/s²]

t = time = 8 [s]

Vf = 24 + (4*8)

Vf = 56 [m/s]

With this velocity, we can calculate the displacement using the following expression.

$v_{f} ^{2} =v_{o} ^{2} +2*a*x$

where

x = distance traveled [m]

56² = 14² + (2*4*x)

x = 2940/(8)

x = 367.5 [m]

Note: The positive sign in the equations is because the car is accelerating, it means its velocity is increasing.

Therefore the total distance is Xt = 14 + 367.5 = 381.5 [m].

4 0

3 years ago