Which statement best describes the relationship between boron and silicon?

Relative to the concept of radiations, a black body is an object capable of absorbing any form of electromagnetic radiation irrespective of its frequency or angle of incidence when incident on such object.

However, the same cannot be said about real bodies as real bodies are those which reflect all rays incident on them completely and uniformly in all directions.

One very important characteristic of black bodies is that they are ideal emmiters.

The concept of emmisivity is brought about by the existence of real bodies .

This is due to the fact that they are only able to emit radiation at a fraction of the black body energy levels.

Please note that by convention, the emmisivity of a real body is always less thaan 1.

As such they are not able to emit as much radiation as a black body at the same temperature.

3 0

2 years ago

A student thinks that any real vibration must be damped. Is the student correct? If so, give convincing reasoning. If not, give

Stels [109]

Answer:

Yes the student is correct

Explanation:

The first law of thermodynamics states that energy can neither be created nor destroyed

The second law of thermodynamics states that the entropy (disorderliness) of an isolated system always increases

Therefore, whereby energy is not supplied to maintain the orderly oscillatory motion with constant amplitude, the amplitude of the system is bound to reduce with time that is the vibration of the system must be damped

6 0

3 years ago

Ted throws an object straight up into the air with an initial velocity of 54 ft/s from a platform that is 40 ft above the ground

elena-s [515]

Answer:

The time it will take for the object to hit the ground will be 4.

Explanation:

You have:

h(t)=−16t²+v0*t+h0

Being v0 the initial velocity (54 ft/s) and h0 the initial height (40 ft) and replacing you get:

h(t)=−16t²+54*t+40

To know how long it will take for the object to touch the ground, the height h(t) must be zero. So:

0=−16t²+54*t+40

Being a quadratic function or parabola: f (x) = a*x² + b*x + c, the roots or zeros of the quadratic function are those values of x for which the expression is 0. Graphically, the roots correspond to the points where the parabola intersects the x axis. To calculate the roots the expression is used:

$\frac{-b+-\sqrt{b^{2}-4*a*c } }{2*a}$

In this case you have that:

a=-16
b= 54
c= 40

Replacing in the expression of the calculation of roots you get:

$\frac{-54+\sqrt{54^{2}-4*(-16)*40 } }{2*(-16)}$ Expresion (A)

and

$\frac{-54-\sqrt{54^{2}-4*(-16)*40 } }{2*(-16)}$ Expresion (B)

Solving the Expresion (A):

$\frac{-54+\sqrt{5476 } }{2*(-16)}= \frac{-54+74}{2*(-16)}=\frac{20}{2*(-16)}=\frac{20}{-32}= -\frac{5}{8}$

Solving the Expresion (B):

$\frac{-54-\sqrt{5476 } }{2*(-16)}= \frac{-54-74}{2*(-16)}=\frac{-128}{2*(-16)}=\frac{-128}{-32}= 4$

These results indicate the time it will take for the object to hit the ground can be -5/8 and 4. Since the time cannot be negative, then <u><em>the time it will take for the object to hit the ground will be 4.</em></u>

6 0

2 years ago