It is called a negative nuetron/atom
Answer:
Number of turns in secondary will be 7
Explanation:
We have given primary voltage 
Number of turns in the primary is 
Secondary voltage is given 
We have to find the number of turns in secondary
We know that 
So 

As the number of turns can not be in decimal so number of turns will be 7
We use the Rydberg Equation for this which is expressed as:
<span>1/ lambda = R [ 1/(n2)^2 - 1/(n1)^2]
</span>
where lambda is the wavelength, where n represents the final and initial states. Brackett series means that the initial orbit that electron was there is 4 and R is equal to 1.0979x10^7m<span>. Thus,
</span>
1/ lambda = R [ 1/(n2)^2 - 1/(n1)^2]
1/1.0979x10^7m = 1.0979x10^7m [ 1/(n2)^2 - 1/(4)^2]
Solving for n2, we obtain n=1.
The minimum initial velocity that the ball must have for it to reach the top of the hill is 21 m/s. The correct option is D.
<h3>What is mechanical energy?</h3>
The mechanical energy is the sum of kinetic energy and the potential energy of an object at any instant of time.
M.E = KE +PE
A boy is trying to roll a bowling ball up a hill. The friction is ignored. The ball must have to reach the top of the hill with a velocity. The acceleration due to gravity, g = 9.8 m/s²
The conservation of energy principle states that total mechanical energy remains conserved in all situations where there is no external force acting on the system.
M.E bottom of hill = M.E on top of hill
Kinetic energy + Potential energy = Kinetic energy + Potential energy
1/2 mu² + 0 = 0 + mgh
At the top of hill, the velocity will become zero. So, final kinetic energy is zero.
Substituting the values, we have
1/2 x u² = 9.8 x 22.5
u = sqrt [2 x9.8 x 22.5 ]
u= 21 m/s
Thus, the minimum initial velocity that the ball must have for it to reach the top of the hill is 21 m/s.
Learn more about mechanical energy.
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When designing tires for a car, an engineer must consider the materials that will be used to fabricate the tires ... both the suitability of the materials for the purpose, and their cost.
For example, the engineer should not design car tires to be made of glass or of silk, since these would not hold up well when driving on concrete roads, and they would need to be replaced too often.
For another example, he should not design car tires to be made of gold or polished diamond, since these would be beyond the price range of most car owners, and also, these tires would be very susceptible to being stolen by nefarious and dishonest individuals in the middle of the night.
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I hope this answer is helpful. The question you posted is a very difficult one, because there are no answer choices listed, and also because the question has the mysterious unknown term "the following" in it.