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Lelu [443]
3 years ago
8

Multiple choice: Sunspots appear dark because

Physics
1 answer:
zepelin [54]3 years ago
3 0

Answer: C. They are regions in which strong magnetic fields make it difficult for fresh supplies of hot, ionized gas to reach the photosphere

Explanation:

Sunspots appear dark because they are regions in which strong magnetic fields make it difficult for fresh supplies of hot, ionized gas to reach the photosphere.

Sunspots are typically cooler than their surroundings. For example, the temperature of a large sunspot can be about 4,000 Kelvin which is lower than the temperature of the photosphere around it which is about 5,800 Kelvin.

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A car speeding down the highway honks its horn, which has a frequency 392 Hz, but a resting bystander hears the frequency 440 Hz
Natali [406]

Answer:

37.42 m/s

Explanation:

We know that apparent frequency, \bar f is given by

\bar f=f\frac {V}{V-V_s} where f is the given frequency in this case 392, V is the speed of sound in air which is given as 343 and V_s is the speed of car which is unknown, \bar f is given as 440 Hz

440=392\times \frac {343}{343-V_s}\\343-V_s=392\times \frac {343}{440}=305.5818182\\V_s=343-305.5818182=37.41818182\approx 37.42 m/s

8 0
3 years ago
An airport has runways only 198 m long. a small plane must reach a ground speed of 39 m/s before it can become airborne. what av
Anarel [89]
S: 198 m 
v=39 m/s 
u=0
t=? 
a=?

v²=u²+2as
(39)²=(0)²+2(a)(198) 
1521=396a
1521/396=a
3.84 m/s^2 = a 

Hope I helped :) 
8 0
3 years ago
The newly formed xenon nucleus is left in an excited state. Thus, when it decays to a state of lower energy a gamma ray is emitt
nevsk [136]

Answer:3.87*10^-4

Explanation:

What is the decrease in mass, delta mass Xe , of the xenon nucleus as a result of this deca

We have been given the wavelength of the gamma ray, find the frequency using c = freq*wavelength.

C=f*lambda

3*10^8=f*3.44*10^-12

F=0.87*10^20 hz

Then with the frequency, find the energy emitted using equation

E=hf E = freq*Plank's constant

E=.87*10^20*6.62*10^-34

E=575.94*10^(-16)

With this energy, convert into MeV from joules.

With the energy in MeV, use E=mc^2 using c^2 = 931.5 MeV/u.

Plugging and computing all necessary numbers gives you

3.87*10^-4 u.

6 0
3 years ago
. Which of the following is the best description about cancer cells?
frozen [14]

Cancer cells are cells that divide relentlessly, forming solid tumors or flooding the blood with abnormal cells. Cell division is a normal process used by the body for growth and repair.

3 0
3 years ago
An engineer is designing a tire for heavy machinery which statement describes the clearest criterion for the solution
Virty [35]

Answer:

I think B tell me if it's right

Explanation:

5 0
3 years ago
Read 2 more answers
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