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3 years ago

The waves that heat a cup of water in the microwave are an example of electromagnetic waves. True or False

Physics

1 answer:

Oksana_A [137]3 years ago

5 0

That's true.

They're radio waves, at the frequency of 2.45 GHz (in all microwave appliances manufactured in the US).

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A 75-hp compressor in a facility that operates at full load for 2500 h a year is powered by an electric motor that has an effici

stealth61 [152]

Answer:

$C = 16544.35\, USD$

Explanation:

The annual electricity cost is:

$C = (\frac{1}{0.93} )\cdot(75\, h.p.)\cdot(0.746\, kW)\cdot(2500\,h)\cdot(\frac{3600\,s}{1\,h} )\cdot(\frac{1\,kWh}{3600\,kJ} )\cdot (0.11\,\frac{USD}{kWh} )$

$C = 16544.35\, USD$

3 0

3 years ago

A solid sphere has a temperature of 614 K. The sphere is melted down and recast into a cube that has the same emissivity and emi

krok68 [10]

Answer:581.87 K

Explanation:

Given

Sphere is melted to form a square

Let the radius of sphere be r and square has a side a

Therefore

$\frac{4\pi}{3}r^3=a^3$

Surface area of sphere $A_s=4\pi r^2$

Surface area of cube $A_c=6a^2$

Total emmisive remains same

Thus $P=A\epsilon \sigma T^4$

$A_sT_s^4=A_cT_c^4$

$\frac{T_c^4}{T_s^4}=\frac{A_s}{A_c}$

$\frac{T_c^4}{T_s^4}=\frac{1}{2}\times \left ( \frac{4\pi}{3}\right )^{\frac{1}{3}}$

$\frac{T_c}{T_s}=\frac{1}{2^{0.25}}\times \left ( \frac{4\pi}{3}\right )^{\frac{1}{12}}$

$T_c=T_s\times \frac{1}{2^{0.25}}\times \left ( \frac{4\pi}{3}\right )^{\frac{1}{12}}$

$T_c=614\times \frac{1.12679}{1.189}$

$T_c=581.87 K$

3 0

3 years ago

Scenario 2: A dam was built California in 1999 to block the Santa Ana River and help generate

8_murik_8 [283]

Answer:

Some of the effects of a dam on the environment includes;

1) Increase in the amount of the greenhouse gases

2) Removal of the natural wetland and ocean carbon sinks

3) Disruption of the sources of nutrients in the ecosystem

4) Destruction of habitats

5) Raising of the sea levels and waste waters

6) Displace villages and communities

7) Dams have a potential to create flood risk

8) Dams lead to increased water loss due to evaporation and transpiration

9) Dams causes earthquakes

Explanation:

Dams are a source of renewable energy and are a means to prevent floods, however, dams can also have detrimental impact on the climate and the environment.

4 0

3 years ago

What is the energy of an electromagnetic wave that has a frequency of

sukhopar [10]

Answer:

$Energy, \; E = 2.6504 * 10^{-34} \; Joules$

Explanation:

Given the following data;

Frequency = 4.0 x 10⁹ Hz

Planck's constant, h = 6.626 x 10-34 J·s.

To find the energy of the electromagnetic wave;

Mathematically, the energy of an electromagnetic wave is given by the formula;

E = hf

Where;

E is the energy possessed by a wave.

h represents Planck's constant.

f is the frequency of a wave.

Substituting the values into the formula, we have;

$Energy, \; E = 4.0 x 10^{9} * 6.626 x 10^{-34}$

$Energy, \; E = 2.6504 * 10^{-34} \; Joules$

8 0

3 years ago

What is kinetic energy?

skad [1K]

Kinetic energy is the energy the makes an object move.

6 0

3 years ago

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