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3 years ago

11

Ultraviolet light of wavelength 3500 Angstrom falls on a potassium surface. The maximum energy of the emitted photoelectrons is

1.6 eV. Find the work function of potassium.

1 answer:

slega [8]3 years ago

8 0

Answer:

The work function of potassium is 1.94 eV.

Explanation:

Given that,

Wavelength $\lambda= 3500\ \AA$

Kinetic energy = 1.6 eV

We need to calculate the energy

Using formula of Energy

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

Put the value into the formula

$E=\dfrac{6.63\times10^{-34}\times3\times10^{8}}{3500\times10^{-10}}$

$E=5.68\times10^{-19}\ J$

$E=5.68\times10^{-19}\times6.24\times10^{18}\ ev$

$E=3.54\ ev$

We need to calculate the work function of potassium

Using formula of work function

$E_{x}=\phi+k_{max}$

Put the value into the formula

$3.54=\phi+1.6$

$\phi=3.54-1.6$

$\phi=1.94\ ev$

Hence, The work function of potassium is 1.94 eV.

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The tension in the rope is constant and equal to 40 N as the block is pulled. What is the instantaneous power (in W) supplied by

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Complete Question:

A 10 kg block is pulled across a horizontal surface by a rope that is oriented at 60° relative to the horizontal surface.

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Power = 54.07 W

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Mass of the block = 10 kg

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a solid metal sphere of radius 3.00m carries a total charge of -5.50. what is the magnitude of the electric field at a distance

aivan3 [116]

Answer:

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Let Q and R are the charge and radius of the solid metal sphere. The solid metal sphere behave as conductor, so total charge Q is on the surface of the sphere.

Electric field inside and outside the metal sphere is :

E = 0 for r ≤ R ( inside )

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Here K is electric constant and r is the distance from the center of the metal sphere.

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(b) Electric field at 2.90 m is zero as r < R i.e. 2.90 m < 3 m from the above equation.

(c) Electric field at 3.10 m is given by the relation as r > R :

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