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3 years ago

Which is the best example of the heat through radiation

2 answers:

8 0

Radiation can be transferred through an MRI, power lines, cordless phones, remote controls, light bulbs , lasers, and CT scans.

ICE Princess25 [194]3 years ago

5 0

Heat from fire or heat from the sun warming your face

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A thermometer having first-order dynamics with a time constant of 1 min is placed in a temperature bath at 100oF. After the ther

sveticcg [70]

Answer:

(a) See below

(b) 103.935 °F; 102.235 °F

Explanation:

The equation relating the temperature to time is

$T = T_{0} + \Delta T\left (1 - e^{-t/\tau} \right )$

1. Calculate the thermometer readings after 0.5 min and 1 min

(a) After 0.5 min

$\begin{array}{rcl}T & = & T_{0} + \Delta T\left (1 - e^{-t/\tau} \right )\\ & = & 100 + 10\left (1 - e^{-0.5/1} \right )\\ & = & 100 + 10\left (1 - e^{-0.5} \right )\\ & = & 100 + 10 (1 - 0.6065)\\ & = & 100 + 10(0.3935)\\ & = & 100 + 3.935\\ & = & 103.935\,^{\circ}F\\\end{array}$

(b) After 1 min

$\begin{array}{rcl}T & = & T_{0} + \Delta T\left (1 - e^{-t/\tau} \right )\\ & = & 100 + 10\left (1 - e^{-1/1} \right )\\ & = & 100 + 10\left (1 - e^{-1} \right )\\ & = & 100 + 10 (1 - 0.3679)\\ & = & 100 + 10(0.6321)\\ & = & 100 + 6.321\\ & = & 106.321\,^{\circ}F\\\end{array}$

2. Calculate the thermometer reading after 2.0 min

T₀ =106.321 °F

ΔT = 100 - 106.321 °F = -6.321 °F

t = t - 1, because the cooling starts 1 min late

$\begin{array}{rcl}T & = & T_{0} + \Delta T\left (1 - e^{-(t - 1)/\tau} \right )\\ & = & 106.321 - 6.321\left (1 - e^{-(2 - 1)/1} \right )\\ & = & 106.321 - 6.321\left (1 - e^{-1} \right )\\ & = & 106.321 - 6.321 (1 - 0.3679)\\ & = & 106.321 - 6.321 (0.6321)\\ & = & 106.321 - 3.996\\ & = & 102.325\,^{\circ}F\\\end{array}$

3. Plot the temperature readings as a function of time.

The graphs are shown below.

6 0

3 years ago

Draw the products formed when cholesterol is treated with [1] bh3·thf; [2] h2o2, −oh. indicate the stereochemistry around any st

Andreas93 [3]

Alkene on Hydration yield Alcohols. When Asymmetric Alkenes are treated with water in the presence of acid they follow Markovnikoff rule, and the Hydrogen of incoming reagent goes to that carbon which contain more number of Hydrogen atoms. The reverse (Anti-Markovnikoff) is done by carrying out Hydroboration reaction.In this case the Hydrogen atom of incoming reagent goes to that carbon which contains less number of Hydrogen atoms. In this reaction both -H and -OH adds in syn fashion. The Hydroboration reaction of Chloestrol is shown below,

3 0

3 years ago

Energy in Devices. An engineer needs to design a device that transforms light energy into sound energy. Describe a design for a

N76 [4]

Answer:

built a special cavity where the electromagnetic quantum states resonate with the natural vibrations of the atoms. In doing so, one cancouple a photon-based oscillator to a mechanical oscillator, controlling the mechanical quantum states with visible light. The result is a prototype of a quantum transducer, a device that converts light energy into mechanical energy (sound energy)

Explanation:

Sound energy is created by vibrating particles of medium that propagates as a wave. So in order to convert light (electromagnetic wave) to sound wave it has to be converted into electric or magnetic signals. Then these signals can be converted into sound waves.

However, if you consider the particle nature of light. It contains momentum and after collision sets the other particles into oscillatory motion but the wavelength of these vibrations is too high to be considered as sound waves.

4 0

4 years ago

How much is one liter

Bas_tet [7]

Answer:

1 litre = 1000 millilitres

8 0

3 years ago

What’s the ionic equation for lithium + water

disa [49]

Answer:

2Li(s) + 2H₂O(ℓ) ⟶ 2Li⁺(aq) + 2OH⁻(aq) + H₂(g)

Explanation:

An ionic equation uses the symbols (aq) [aqueous] to indicate molecules and ions that are soluble in water, (s) [solid] to indicate insoluble solids, and (ℓ) to indicate substances (usually water) in the liquid state.

In this reaction, solid lithium reacts with liquid water to form soluble lithium hydroxide and gaseous hydrogen .

1. Molecular equation

2Li(s) + 2H₂O(ℓ) ⟶ 2LiOH(aq) + H₂(g)

2. Ionic equation

Lithium hydroxide is a soluble ionic compound, so we write it as hydrated ions.

2Li(s) + 2H₂O(ℓ) ⟶ 2Li⁺(aq) + 2OH⁻(aq) + H₂(g)

7 0

3 years ago