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Reptile [31]
3 years ago
9

Which lanthanide forms a compound that enables you to see red on acomputer screen!​

Physics
1 answer:
jeka943 years ago
5 0

Answer:

Europium

Explanation:

You might be interested in
How much thermal energy is
Alex17521 [72]

Answer:

Qt = 940500 [J]

Explanation:

In order to solve this problem and understand it well, we must analyze that the ice melts or changes phase at a temperature of 0 [°c], then the water at a temperature of 100 [°C] evaporates or changes phase. That is, we have 5 different stages of water (initially in the form of ice), which are:

-) From -30 [°C] to 0 [°C] = Sensible change of temperature

-) At 0 [°C] = Latent heat of melting ice = 334 x 10³ [J/kg]

-) From 0 [°C] to 100 [°C] = Sensible change of temperature

-) At 100 [°C] = Latent heat of fusion for water = 2260 x 10³ [J/kg]

-) From 100 [°C] to 130 [°C] = Sensible change of temperature (superheating)

We can calculate the sensible heat of any process with the following expression:

Q=m*C_{p}*(T_{f}-T_{i})

where:

Q = heat or thermal energy [J]

m = mass of the body or substance = 300 [g]

Cpw = specific heat of the water = 4180 [J/kg*°C]

Cpi = specific heat of the ice = 2090 [J/kg*°C]

Tfinal = final temperature of the process [°C]

Tinicial = initial temperature of the process [°C]

And for some latent heat process, we can calculate the thermal energy using the following expression:

Q_{lat}=m*Dh_{fus/eva}

where:

Dhfus/eva = Fusion heat or latent heat [J/kg]

So, we need to calculate the fice processes.

Q_{1}=0.3*2090*(0-(-30))\\Q_{1}=18810 [J]\\Q_{2}=0.3*334*10^{3} \\Q_{2}=100200[J]\\Q_{3}=0.3*4180*(100-0)\\Q_{3}=125400[J]\\Q_{4}=0.3*2260*10^{3}\\Q_{4}=678000[J]\\Q_{5}=0.3*2010*(130-100)\\Q_{5}=18090[J]

And the final step is the sum of all the five heat processes.

Q_{t}=Q_{1}+Q_{2}+Q_{3}+Q_{4}+Q_{5}\\Q_{t}=18810+100200+125400+678000+18090\\Q_{t}=940500[J]

8 0
2 years ago
What is the most precise method for recording data points during an experiment? A. plotting the data point on an X-Y graph B. cr
natulia [17]
The answer is C. Filling a table with the changed and measured data values
5 0
3 years ago
Read 2 more answers
A reciprocating compressor is a device that compresses air by a back-and-forth straight-line motion, like a piston in a cylinder
Stella [2.4K]

Answer:

The temperature change per compression stroke is 32.48°.

Explanation:

Given that,

Angular frequency = 150 rpm

Stroke = 2.00 mol

Initial temperature = 390 K

Supplied power = -7.9 kW

Rate of heat = -1.1 kW

We need to calculate the time for compressor

Using formula of compression

\terxt{time for compression}=\text{time for half revolution}

\terxt{time for compression}=\dfrac{1}{2}\times T

\terxt{time for compression}=\dfrac{1}{2}\times \dfrac{1}{f}

Put the value into the formula

\terxt{time for compression}=\dfrac{1}{2}\times \dfrac{1}{150}\times60

\terxt{time for compression}=0.2\ sec

We need to calculate the rate of internal energy

Using first law of thermodynamics

U=Q-W

\dfrac{\Delta U}{\Delta t}=\dfrac{\Delta Q}{\Delta t}-\dfrac{\Delta W}{\Delta t}

Put the value into the formula

\dfrac{\Delta U}{\Delta t}=(-1.1)-(7.9)

\dfrac{\Delta U}{\Delta t}=6.8\ kW

We need to calculate the temperature change per compression stroke

Using formula of rate of internal energy

\dfrac{\Delta U}{\Delta t}=\dfrac{nc_{v}\Delta \theta}{\Delta t}

\Delta\theta=\dfrac{\Delta U}{\Delta t}\times\dfrac{\Delta t}{n\times c_{c}}

Put the value into the formula

\Delta \theta=6.8\times10^{3}\dfrac{0.2}{2.0\times20.93}

\Delta\theta=32.48^{\circ}

Hence, The temperature change per compression stroke is 32.48°.

6 0
3 years ago
Which of Newton's laws of motion describes the motion of an object that has a net<br> force of ON?
algol [13]

Newton's first and second laws of motion both do, but I think the one you're looking for is: <em>The First Law of Motion</em>.  That description is a little more direct.

It says that if an object is not acted on by a net external force, then it continues in "constant, uniform motion".

3 0
2 years ago
A 6 N and a 10 N force act on an object. The moment arm of the 6 N force is 0.2 m. If the 10 N force produces five times the tor
Levart [38]

Answer:

The moment arm is 0.6 m

Explanation:

Given that,

First force F_{1}=6\ N

Second force F_{2}=10\ N

Distance r = 0.2 m

We need to calculate the moment arm

Using formula of torque

\tau=Force\times lever\ arm

So, Here,

\tau_{2}=5 \tau_{1}

We know that,

The torque is the product of the force and distance.

Put the value of torque in the equation

F_{2}\times d_{2}=5\times F_{1}\times r_{1}

r_{2}=\dfrac{5\times F_{1}\times r_{1}}{F_{2}}

Where, F_{1}=First force

F_{1}=First force

F_{2}=Second force

r_{1}= distance

Put the value into the formula

r_{2}=\dfrac{5\times6\times0.2}{10}

r_{2}=0.6\ m

Hence, The moment arm is 0.6 m

6 0
3 years ago
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