Electromagnets have certain advantages over permanent magnets. One of the major advantage is, the amount of electric current can easily be controlled, in turn, magnetic field can be controlled. Out of all the options, option D would be the best answer.
In short, Your Answer would be option D) Electromagnets can easily be turned on and off.
Hope this helps!
Answer: In a longitudinal wave, the crest and trough of a transverse wave correspond respectively to the compression, and the rarefaction. A compression is when the particles in the medium through which the wave is traveling are closer together than in its natural state, that is, when their density is greatest.
If the billiard ball is going at the constant speed and contains its mass then the momentum WONT be changing. But realistically you have external forces like friction and air resistance changing the velocity thus changing the momentum. In this case momentum is not conserved because you're introduction an external force.
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<h2 /><h2 /><h2>Acceleration : </h2>
Acceleration is a vector quantity that is defined as ❝ rate of change in velocity ❞
And as per the question, the plane can go from 0 miles to 100 miles/hour in 10 seconds that shows rate of change in its velocity. that is :
from 0 miles/hour to 100 miles/hour. hence Acceleration is the quantity being described about the new plane.
[ v = final velocity, u = initial velocity, t = time ]
So, the Acceleration of the new plane is 10 miles/hour²
<span>3640 m/s
The de Broglie wavelength of a particle is expressed by the equation:
λ = h/p
where
λ = wavelength
h = Planck constant
p = momentum
so let's solve for momentum and the substitute the known values and calculate:
λ = h/p
λp = h
p = h/λ
p = 6.62607004x10^-34 Js/2x10^-7 m
p = 6.62607004x10^-34 kg*m^2/s^2 * s/2x10^-7 m
p =3.31303502x10^-27 kg*m/s
Now momentum is defined as mass times velocity. And the mass of an electron is 9.10938356Ă—10^-31 kg. So
p = mv
p/m = v
3.31303502x10^-27 kg*m/s / 9.10938356Ă—10^-31 kg = v
3.63694754774384x10^3 m/s = v
Rounding to 3 significant figures gives 3.64x10^3 m/s or 3640 m/s. That velocity is low enough that we don't need to worry about relativistic effects.</span>
