you may just select the word answer and then without cutting it u may start to type ur answer then it will be in bold letter
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The two most important minerals you need to do the test are <span>Corundum and quartz. You use that to do scratch test</span>
Refractive index is the ration of sin i to sin r where i is the incident angle and r is the refraction angle.
Therefore, refractive index = sin 79.5 / sin 39.6
= 1.542
The refractive index may be given by the ratio of refractive index of medium 2 to refractive index of medium 1.
Therefore, 1.542 = n/1.0003
n = 1.5425
≈ 1.54
Medium 2 is sodium chloride, refractive index of 1.54
Answer: 0.0138 m^2 = 138 cm^2
Explanation:
The thermal expansion is the term use for the physical phenomena of dilation of the objects when they are exposed to changes in temperature.
The objects dilate when they are heated and contract when they are cooled.
The dilation is proportional to the change in temperatur.
For linear dilation, the proportionality constant is called linear dilation coefficient of the materials, it is named α and is measured in °C ^-1.
ΔL = α * Lo * ΔT, which means that the dilation (or contraction) is proportional to the product of the original length (Lo) and the change of temperature (ΔT).
There is also superficial dilation, for which the dilation is:
ΔA = β * Ao * ΔT, which means that the superficial dilation (or contraction) is proportional to the product of the original area (Ao) and the change of temperature (ΔT).
It is very interesting and important to solve problems that β = 2α, because regularly you will find the values of α for different materials and so, you just to multiply it times 2 to use β.
For this problem:
- Original area, Ao = area of the flat roof at - 10°C = 2.0m * 3.0m = 6.0 m^2.
- α for aluminum = 24 * 10^ -6 °C^-1.
- ΔT = 38°C - (-10°C) = 48°C
So, ΔA = 6.0m^2 * (2 * 24*10^-6 °C&-1) * 48°C = 0.0138 m^2
And that is the area that should stick out in summer to fit the structure during cold winter nights.
You can pass that number to cm^2 to grasp better the idea of this size:
0.0138 m^2 * (100 cm)^2 / m^2 = 138 cm^2
Answer:
a. Both wires have the same resistivity
Explanation:
For the resistance of a wire , following formula holds good .
R = ρ l / S , R is resistance , l is length , S is cross sectional area and ρ is resistivity of the material that the wire is made of. Resistance is dependent on length and cross sectional area but resistivity does not depend upon length or cross sectional area . It only depends upon the type of material.
If we replace copper wire with aluminium wire , then resistivity will change .
Hence , since the wire remains made of copper , resistivity will not change.
