Iplace a 500-g ice cube (initially at 0°c) in a styrofoam box with wall thickness 1.0 cm and total surface area 600 cm2 .

if the air surrounding the box is at 20°c and after 4 hours the ice is completely melted, what is the conductivity of the styrofoam material? (lf = 80 cal/g)
a. 9.6 × 10−5cal/s⋅cm⋅°c
b. 2.8 × 10−6cal/s⋅cm⋅°c
c. 1.15 × 10−2cal/s⋅cm⋅°c
d. 2.3 × 10−4cal/s⋅cm⋅°c

Para resolver este problema es necesario aplicar los conceptos relacionados a la conductividad térmica, para lo cual se tiene matematicamente que

Where,

K = thermal conductivity

A = Cross-sectional Area

= Change at temperature

x = Distance

= Difference of time

= Heat exchange energy

Our values are given as follow,

The total heat required to change the phase of ice would be

Where Lf Latent heat of fussion and m is the mass.

Replacing we would have:

Therefore the correct answer is D.

quantum mechanics or quantum physics is physics of very small objects (particles) and physical entities.

quantum physics has some parallels to our macro world and some pretty unique ideas which theoretically and mathematically proven to be true even though we will never be able to access them because of our size.

there are many types of particles: subatomic, elementary etc.

subatomic means they are smaller than atom, elementary means they are at the very basis of everything.

subatomic particles are for eg. protons, neutrons but not electrons.

elementary particles are categorised into 3 groups by what they do.

these 3 groups are quarks, leptons and bosons.

light for example is a particle more precisely a photon a part of leptons.

proton (subatomic particle) is made out of 2 up quarks and 1 down quark each of these has a fractional charge like . (i crazy)

most famous scientist who contributed to this physics are:

the topic itself us understand a lot and will probably be vastly used in the future (quantum computers, understanding the big bang,

we also must not forget quantum effects like:

and there is more. but probably too much for this answer to be consistent due to my average understanding of this topic.

hope this you understand quantum mechanics a little more. i'm not an expert in the topic (so don't be like wth if you are an expert) but i'm very interested in it.

anyways quantum physics is a very hard topic (harder than physics (perhaps)) therefore searching for every information there is about it and learning it is unfortunately impossible (you can only specialise into 1 - 3 things or more (perhaps

have fun and i wish you luck!

r3t40