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3 years ago

Calculate the energy transferred from a glass of water in order to just melt 100 g of ice cubes at 0°C.

Physics

1 answer:

Ludmilka [50]3 years ago

3 0

Answer:

34000 J or 34 kJ

Explanation:

From the question, The energy needed to just melt the ice cube does not requires any external temperature or change in temperature, Hence it is called latent heat

By Applying,

Q' = C'm........................ Equation 1

Where Q' = Latent heat, C' = Specific latent heat of fusion of water, m = mass of ice.

Given: C' = 340000 J/kg, m = 100 g = 0.1 kg

Substitute into equation 1

Q' = 0.1(340000)

Q' = 34000 J

Q' = 34 kJ

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What temperature will 1L of H20 at 200°F become when a piece of copper,0.25kg at 260.928K, comes into contact with water?

Lady_Fox [76]

Answer:

Explanation:

mass of 1 L water = 1 kg .

200⁰F = (200 - 32) x 5 / 9 = 93.33⁰C .

260.928 K = 260.928 - 273 = - 12.072⁰C .

water is at higher temperature .

Let the equilibrium temperature be t .

Heat lost by water = mass x specific heat x fall of temperature

= 1 x 4.2 x 10³ x ( 93.33 - t )

Heat gained by copper

= .25 x .385 x 10³ x ( t + 12.072 )

Heat lost = heat gained

1 x 4.2 x 10³ x ( 93.33 - t ) = .25 x .385 x 10³ x ( t + 12.072 )

93.33 - t = .0229 ( t + 12.072)

93.33 - t = .0229 t + .276

93.054 = 1.0229 t

t = 90.97⁰C .

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2 years ago

the amplitude of the wave is which of the following A. Resonance B. Reflection C. Energy D. Magnitude

OLga [1]

D.Magnitude is the answer

8 0

3 years ago

Glass is transparent to visibile light under normal conditions; however, at extremely high intensities, glass will absorb most o

8_murik_8 [283]

Answer:

3 photons

Explanation:

The energy of a photon E can be calculated using this formula:

$E=\frac{hc}{\lambda}$

Where $h$ corresponds to Plank constant (6.626070x10^-34Js), $c$ is the speed of light in the vacuum (299792458m/s) and $\lambda$ is the wavelength of the photon(in this case 800nm).

$E=\frac{hc}{\lambda}=\frac{(6.626070\times10^{-34})(299792458)}{800\times10^{-9}}=\frac{1.986445812\times10^-25}{800}=2.483057265\times10^{-19}J$

Tranform the units

$1eV=1.602176634\times10^{-19}J\\2.483057265\times10^{-19}J(\frac{1eV}{1.602176634\times10^{-19}J})=1.549802445eV$

The band Gap is 4eV, divide the band gap between the energy of the photon:

$\frac{4ev}{1.549802445eV}=2.508974118$

Rounding to the next integrer: 3.

Three photons are the minimum to equal or exceed the band gap.

4 0

3 years ago

What element are the cores of massive stars made of when a supernova occurs?

Studentka2010 [4]

I think its C. Oxygen

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3 years ago

A brick lands 10.1 m from the base of a building. If it was given an initial velocity of 8.6 m/s [61º above the horizontal], how

Montano1993 [528]

<h2>Answer: 10.52m</h2><h2 />

First, we have to establish the <u>reference system</u>. Let's assume that the building is on the negative y-axis and that the brick was thrown at the origin (see figure attached).

According to this, the initial velocity $V_{o}$ has two components, because the brick was thrown at an angle $\alpha=61\º$ :