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slava [35]
3 years ago
12

The spectrum of a distant star shows that one in 2 e6 of the atoms of a particular element is in its first excited state 7.5 eV

above the ground state. What is the temperature of the star? (You can ignore the other excited states and assume the ratio of statistical weights is 4
Physics
1 answer:
Alchen [17]3 years ago
5 0

Answer:

The temperature of star is 5473.87 K

Explanation:

Given:

Energy difference \Delta E = 7.5 eV

The ratio of number of particle \frac{N_{f} }{N_{i} } = \frac{1}{2 \times 10^{6} }

Degeneracy ratio \frac{g_{f} }{g_{i} }  = 4

From the formula of boltzmann distribution for population levels,

     \frac{N_{f} }{N_{i} } =\frac{g_{f} }{g_{i} }  e^{-\frac{\Delta E}{kT} }

Where k = boltzmann constant = 8.62 \times 10^{-5} \frac{eV}{K}

     \frac{1}{2 \times 10^{6} } =4  e^{-\frac{7.5 eV}{8.62 \times 10^{-5} T} }

  8 \times 10^{6} } = e^{\frac{7.5 eV}{8.62 \times 10^{-5} T} }

\ln(8 \times 10^{6})  = {\frac{7.5 eV}{8.62 \times 10^{-5} T} }

  T  = {\frac{7.5 eV}{8.62 \times 10^{-5} \ln(8 \times 10^{6})} }

  T = 5473.87 K

Therefore, the temperature of star is 5473.87 K

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Give examples of plants that can reproduce by vegetative reproduction.​
marishachu [46]

Answer:

Some examples of vegetative propagation are farmers creating repeated crops of apples, corn, mangoes or avocados through asexual plant reproduction rather than planting seeds. Vegetative propagation can be accomplished from side-shoots, slips, stems and sections of tubers, bulbs or rhizomes.

Explanation:

5 0
3 years ago
A boy throws a snowball straight up in the air with an initial speed of 4.50 ft/s from a position 4.00 ft above the ground. The
IgorC [24]

Answer:

a) 0.658 seconds

b) 0.96 inches

Explanation:

v=u+at\\\Rightarrow 0=4.5-32.1\times t\\\Rightarrow \frac{-4.5}{-32.1}=t\\\Rightarrow t=0.14 \s

Time taken by the ball to reach the highest point is 0.14 seconds

s=ut+\frac{1}{2}at^2\\\Rightarrow s=4.5\times 0.14+\frac{1}{2}\times -32.1\times 0.14^2\\\Rightarrow s=0.315\ ft

The highest point reached by the snowball above its release point is 0.315 ft

Total height the snowball will fall is 4+0.315 = 4.315 ft

s=ut+\frac{1}{2}at^2\\\Rightarrow 4.315=0t+\frac{1}{2}\times 32.1\times t^2\\\Rightarrow t=\sqrt{\frac{4.315\times 2}{32.1}}\\\Rightarrow t=0.518\ s

The snowball will reach the bank at 0.14+0.518 = 0.658 seconds after it has been thrown

v=u+at\\\Rightarrow v=0+32.1\times 0.518\\\Rightarrow v=16.62\ ft/s

v^2-u^2=2as\\\Rightarrow s=\frac{v^2-u^2}{2a}\\\Rightarrow s=\frac{0^2-16.62^2}{2\times -100\times 3.28}\\\Rightarrow s=0.42\ ft

The snowball goes 0.5-0.42 = 0.08 ft = 0.96 inches

8 0
3 years ago
PLEASE HELP!!
leva [86]
I think the answer is B
8 0
2 years ago
How will unbalanced forces affect the speed and direction of an object
azamat

Answer:

Explanation:

Unbalanced forces will result in the presence of acceleration. The formula

F net = ma

says that if there is a net force present and the object in question has a mass, then an acceleration is present. Now acceleration is constant in this situation because nowhere does it say the acceleration is changing. If acceleration is constant then the velocity is increasing at a steady pace (think linear function!).

The direction of the object depends on the direction that the net force is in. If the net force is to the left, then that object will accelerate to the left.

Hope this helps :)

3 0
3 years ago
How fast did Newton decide a cannon ball shot out in order to escape Earth’s gravity?
arsen [322]

Plugging in for the Earth's mass and for G, we have 11.2 km/s for the escape velocity for an object launched from the Earth's surface. This is about 25,000 miles per hour

7 0
3 years ago
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