All categories

3 years ago

Where does a phase change occur

Physics

2 answers:

natta225 [31]3 years ago

8 0

Answer:

Explained

Explanation:

Phase change is a physical process in which a substance goes from one phase to another. Usually changes occur at a constant temperature and at this constant temperature heat is either given or extracted from the object. And the nature of phase change depends upon the direction of heat transfer.

heat going into the system changes a solid into gas or liquid, whereas heat coming out of the system changes gases to liquid and liquids to solids.

il63 [147K]3 years ago

3 0

A phase change is occuring; the liquid water is changing to gaseous water, or steam. On a molecular level, the intermolecular forces between the water molecules are decreasing. The heat is providing enough energy for the water molecules to overcome these attractive forces.

You might be interested in

One and one-half moles of an ideal monatomic gas expand adiabatically, performing 7900 J of work in the process. What is the cha

mart [117]

Answer:

The temperature change is -633.15K

Explanation:

If we considered the expansion as a reversible one (to be adiabatic is one of the requirements), the work done by expansion can be written as:

$W=-n*P(v_2-v_1)=-P*(V_2-V_1)$ Where 2 and 1 subscripts mean the final and the initial state respectively. The equation negative sign says that for an expansion of the gas, the system is making work, so the energy is going out of the system.

Using the ideal gas equation, it is possible to change volume and pressure by temperatures:

$PV_2=(nRT_2)\\PV_1=nRT_1$

So,

$W=-nR(T_2-T_1)$

$(T_2-T_1)=\frac{-W}{nR}=\frac{-7900J}{(1.5mol*8.314\frac{J}{molK})}=-633.5K$

This result makes sense considering that the volume increases, so it is expected that the temperature decreases.

4 0

3 years ago

What is the direction of propagation of the wave if E⃗ =Ei^,B⃗ =−Bj^. Express the direction of the propagation vector, P⃗ , as a

nataly862011 [7]

Answer with Explanation:

We are given that

Electric field vector= $\vec{E}=E\hat{i}$

Magnetic field vector= $\vec{B}=-B\hat{j}$

We have to find the direction of propagation of the wave.

We know that

The direction of propagation of wave= $\vec{E}\times \vec{B}$

The direction of propagation of wave= $\hat{i}\times (-\hat{j})=-\hat{k}$

Because ( $\hat{i}\times \hat{j}=\hat{k}$ )

The wave propagate in -z direction.

Therefore, the component of the vector is (0,0,-1).

Hence, the direction of the propagation of wave is - z direction and component of direction of propagation vector is (0,0,-1).

6 0

4 years ago

10. A triply ionized beryllium atom is in the ground state. It absorbs energy and makes a transition to the n = 5 excited state.

Xelga [282]

Answer:

$\lambda=1282\ nm$

Explanation:

$E_n=-2.179\times 10^{-18}\times \frac{1}{n^2}\ Joules$

For transitions:

$Energy\ Difference,\ \Delta E= E_f-E_i =-2.179\times 10^{-18}(\frac{1}{n_f^2}-\frac{1}{n_i^2})\ J=2.179\times 10^{-18}(\frac{1}{n_i^2} - \dfrac{1}{n_f^2})\ J$

$\Delta E=2.179\times 10^{-18}(\frac{1}{n_i^2} - \dfrac{1}{n_f^2})\ J$

Also, $\Delta E=\frac {h\times c}{\lambda}$

Where,

h is Plank's constant having value $6.626\times 10^{-34}\ Js$

c is the speed of light having value $3\times 10^8\ m/s$

So,

$\frac {h\times c}{\lambda}=2.179\times 10^{-18}(|\frac{1}{n_i^2} - \dfrac{1}{n_f^2}|)\ J$

$\lambda=\frac {6.626\times 10^{-34}\times 3\times 10^8}{{2.179\times 10^{-18}}\times (|\frac{1}{n_i^2} - \dfrac{1}{n_f^2}|)}\ m$

So,

$\lambda=\frac {6.626\times 10^{-34}\times 3\times 10^8}{{2.179\times 10^{-18}}\times (|\frac{1}{n_i^2} - \dfrac{1}{n_f^2}|)}\ m$

Given, $n_i=5\ and\ n_f=3$

$\lambda=\frac{6.626\times 10^{-34}\times 3\times 10^8}{{2.179\times 10^{-18}}\times (\frac{1}{5^2} - \dfrac{1}{3^2})}\ m$

$\lambda=\frac{10^{-26}\times \:19.878}{10^{-18}\times \:2.179\left(|\frac{1}{25}-\frac{1}{9}\right)|}\ m$

$\lambda=\frac{19.878}{10^8\times \:2.179\left(|-\frac{16}{225}\right|)}\ m$

$\lambda= 1.2828\times10^{-6}$

1 m = 10⁻⁹ nm

$\lambda=1282\ nm$

6 0

3 years ago

What happens when the fuel in a car engine combustion?

Trava [24]

In a spark ignition engine, the fuel is mixed with air and then inducted into the cylinder during the intake process. After the piston compresses the fuel-air mixture, the spark ignites it, causing combustion. The expansion of the combustion gases pushes the piston during the power stroke.

Credit: Department of Energy

5 0

3 years ago

Help me please (*￣(ｴ)￣*)

Len [333]

Answer:

1) Are always conservative

Explanation:

Elastic forces are always conservative.

Hope it helps you.

please mark as the brainliest answer.

3 0

3 years ago

Read 2 more answers