Answer:
a
e(k) = \frac{2a}{c} * sin (\frac{k*a}{2} )
b
G_{v} = \frac{d e(k ) }{dk } = \frac{a^2}{c} * cos (\frac{k* a}{2} )
Explanation:
From the question we are told that
The velocity of transverse waves in a crystal of atomic separation is
Generally the dispersion relation is mathematically represented as
=> 
=> 
=> 
Generally the group velocity is mathematically represented as
Answer:
F = -8440.12 N
the magnitude of the average force needed to hold onto the child is 8440.12 N
Explanation:
Given;
Mass of child m = 16 kg
Speed of each car v = 59.0 mi/h = 26.37536 m/s
Time t = 0.05s
Applying the impulse momentum equation;
Impulse = change in momentum
Ft = ∆(mv)
F = ∆(mv)/t
F = m(∆v)/t
Where;
F = force
t = time
m = mass
v = velocity
Since the final speed of the car is zero(at rest) then;
∆v = 0 - v = -26.37536 m/s
Substituting the given values;
F = 16×-26.37536/0.05
F = -8440.1152 N
F = -8440.12 N
the magnitude of the average force needed to hold onto the child is 8440.12 N
Answer:
b.) All these technologies use radio waves, including high-frequency microwaves
d.) Microwave ovens emit in the same frequency band as some wireless Internet devices.
e.) The radiation emitted by wireless Internet devices has the shortest wavelength of all the technologies listed above.
f.) All these technologies emit waves with a wavelength in the range of 0.10 to 10.0 m.
Explanation:
For option D. The frequency range of microwave ovens is 2450 MHz = 2.4 GHz, which intersects with wireless internet technology with range of 2.4 to 2.6 GHz.
For E, wavelenght and frequency are inversely proportional. Wireless internet service has the greatest frequency band and hence the shortest wavelenght band.
For F, in all these radiations, the highest Freq is 2.6 GHz and the lowest is 40 MHz. Wavelenght is speed of light (3x10^8 m/s) divided by the frequency.
2.6 GHz = 2.6x10^9 Hz
Wavelenght = 3x10^8 ÷ 2.6x10^9 = 0.1 m
40 MHz = 40x10^6
Wavelenght = 3x10^8 ÷ 40x10^6 = 7.5 m
Answer:
BA
0
Explanation:
B = Magnetic field
A = Area
= Angle
t = Time taken
Before rotation the magnetic flux is given by
Magnetic flux is BA
After rotation the magnetic flux is given by
The magnetic flux is 0
Magnitude of emf is given by
The magnitude of the average emf induced in the entire coil is
Ultravoilent rays is an type of an electromegnetic wave with wavelength 10nm .Ultraviolet wave is used by doctors in order to keep the wounds away from bacteria.
<h3>What is ultravoilent wave ?</h3>
Ultravoilent rays is an type of an electromegnetic wave with wavelength 10nm. Ultravoilent wave is directly comes frim the sun. It is classified into the UV(A) , UV(B),UV(B).
Ultravoilet rays also effects the human eyes that s why sun glasses are used. The experiments here are compared and quantified to the effectiveness of the sunscreens with various strengths.
To learn more about the ultravoilent wave refr to the link;
brainly.com/question/19706211
