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It is known that the kinetics of recrystallization for some alloy obeys the Avrami equation, andthat the value of n in the expon

trapecia [35]

Answer: $8.76\times 10^{-3} min^{-1}$

Explanation:

Given

n=5

0.3 fraction recrystallize after 100 min

According to Avrami equation

$y=1-e^{-kt^n}$

where y=fraction Transformed

k=constant

t=time

$0.3=1-e^{-k(100)^5}$

$e^{-k(100)^5} =0.7$

Taking log both sides

$-k\cdot (10^{10}=\ln 0.7$

$k=3.566\times 10^{-11}$

At this Point we want to compute $t_{0.5}\ i.e.\ y=0.5$

$0.5=1-e^{-kt^n}$

$0.5=e^{-kt^n}$

$0.5=e^{-3.566\times 10^{-11}\cdot (t)^5}$

taking log both sides

$\ln 0.5=-3.566\times 10^{-11}\cdot (t)^5$

$t^5=1.943\times 10^{10}$

$t=114.2 min$

Rate of Re crystallization at this temperature

$t^{-1}=8.76\times 10^{-3} min^{-1}$

3 0

3 years ago

What does malleablity means

daser333 [38]

Able to be hammered or pressed permanently out of shape without breaking or cracking.

3 0

3 years ago

When would a scientist accept the alternative

vredina [299]

Answer:

B.) if statistical results are significant

Explanation:

If a scientist accepts the null hypothesis, then there is enough evidence to reject the null hypothesis.

This means that the p-value is less than the significance level.

When the scientist accepts the alternative hypothesis, it means the statistical results are significant.

The correct answer is B.

3 0

3 years ago

2.Write the formula associating energy with power

Alika [10]

Answer:

$Power = \frac {mgh}{time}$

Explanation:

2. Power can be defined as the energy required to do work per unit time.

Mathematically, it is given by the formula;

$Power = \frac {Energy}{time}$

3. Potential energy can be defined as an energy possessed by an object or body due to its position.

Mathematically, potential energy is given by the formula;

$P.E = mgh$

Where,

P.E represents potential energy measured in Joules.

m represents the mass of an object.

g represents acceleration due to gravity measured in meters per seconds square.

h represents the height measured in meters.

4. Substituting the equation in 3 into equation in 2 above, we have;

$Power = \frac {mgh}{time}$

5 0

3 years ago

While studying physics at the library late one night, you noticethe image of the desk lamp reflected from the varnished tabletop

Natalija [7]

<h2>Answer: 1.73</h2>

Explanation:

The situation described here is known as polarization by reflection. This was discovered by Scottish physicist David Brewster and then formulated the law that bears his name:

<em>"When a beam of light hits the surface that separates two non-conducting media characterized by different electromagnetic characteristics (electrical permittivity and magnetic permeability), part of it is reflected back to the source medium, and part is transmitted to the second medium."</em>

This polarization happens when the light incides at a specific angle, called the Brewster angle ( $\theta_{B}$ ), which is given by the following formula (<u>taking into account that generally the magnetic permeabilities of the two media involved do not vary):</u>

$tan\theta_{B}=\frac{n_{2}}{n_{1}}$ (1)

Where $n_{2}$ is the index of refraction of the second medium (the varnish in this case) and $n_{1}=1$ is the index of refraction of the first medium (the air).

Now, if we are told the angle between the incident and reflected rays is $120\°$ , this means the incident angle is the half ( $60\°$ ), which is the Brewster angle in this case.

So, $\theta_{B}=60\°$ (2)

Rewriting (1) with this incident ray angle:

$tan(60\°)=\frac{n_{2}}{1}$ (3)

$n_{2}=tan(60\°)$

Finally we obtain the index ofrefraction of the varnish:

$n_{2}=1.732$

5 0

4 years ago