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Neporo4naja [7]

4 years ago

6

Which of the following statements about horizons is true?. a. They are characterized by whether they are solid, liquid, or gas..

b. They are represented by Roman numerals.. c. All soils have completely different horizon patterns.. d. They are defined by their different physical features.

1 answer:

garik1379 [7]4 years ago

3 0

<span>The answer is d. they are defined by their different physical features. A soil horizon is a layer in a soil profile. Horizons are defined by different physical features such as colour or texture. Other features include, structure and permeability. Each horizon is represented by a letter; A,B,C....</span>

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In a photoelectric experiment it is found that a stopping potential of 1.00 V is needed to stop all the electrons when incident

kiruha [24]

Answer:

Planck’s constant is $6.9*10^{-34} Js$

work function of metal is $5.846*10^{-19}$

Explanation:

The maximum kinetic energy from electron from photoelectric effect is given by

$\K_{max}=eV_o$ where $V_o$ is applied voltage and e is charge on electron and substituting charge on electron by $1.6*10^{-19}$ and 1.00 V for $V_o$

$K_{max}=1.6*10^{-19}*1=1.6*10^{-19} J$

Considering that the wavelength, \lambda of light used is given as $278*10^{-9} m$

Energy of light is given by

$E=\frac {hc}{ \lambda}$ where $\lambda$ is the wavelength, h is Planck’s constant and c is speed of light. Taking c for $3*10^{8} m/s$

Substituting values of wavelength and speed of light we obtain

$E=\frac {h*3*10^{8}}{278*10^{-9}}=h1.07914*10^{15} J$

If work function is $\phi$ then

$E=\phi + k_{max}$ hence

$h1.07914*10^{15} J=\phi +1.6*10^{-19} J$ ------- Equation 1

Energy corresponding to wavelength of 207 nm is

$E=h\frac {3*10^{8} m/s}{207*10^{-9}}=h(1.45*10^{15}}) J$

Maximum kinetic energy of electrons when $V_o$ is 2.6 V becomes

$K_{max}=(1.6*10^{-19})*2.6V=4.16*10^{-19} J$

From $E=\phi + k_{max}$ and substituting $h(1.45*10^{15}}) J$ for E and $4.16*10^{-19} J$ for $K_{max}$ we have

$h(1.45*10^{15}}) J=\phi +4.16*10^{-19} J$ ------ Equation 2

Equation 2 minus equation 1 gives

$h3.71*10^{14}=2.56*10^{-19}$

$h=\frac {2.56*10^{-19}}{3.71*10^{14}}\approx 6.9*10^{-34} Js$

Therefore, Planck’s constant is $6.9*10^{-34} Js$

Recalling equation 1 and substituting back the value of h as obtained

$h1.07914*10^{15} J=\phi +1.6*10^{-19} J$

$(6.9*10^{-34})*(1.07914*10^{15})=\phi +1.6*10^{-19} J$

$\ph=(6.9*10^{-34})*(1.07914*10^{15})-(1.6*10^{-19})=5.846*10^{-19}$

Therefore, work function of metal is $5.846*10^{-19}$

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Answer is 29.1 mol or 525 g

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Hello!

These atoms are isotopes

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