the anode voltage of a photocell is kept fixed the

The anode voltage of a photocell is kept fixed. The wavelength $$\lambda $$ of the light falling on the cathode is gradually changed. The plate current $$I$$ of the photocell varies as follows

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Answer : Modern Physics Miscellaneous mcq option image

Solution :
As $$\lambda $$ decreases, $$\nu $$ increases and hence the speed of photoelectron increases. The chances of photo electron to meet the anode increases and hence photo electric current increases.

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Releted Question 1

The maximum kinetic energy of photoelectrons emitted from a surface when photons of energy $$6\,eV$$ fall on it is $$4\,eV.$$ The stopping potential, in volt, is

A. 2

B. 4

C. 6

D. 10

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Releted Question 2

Electrons with energy $$80\,keV$$ are incident on the tungsten target of an X-ray tube. $$K$$-shell electrons of tungsten have $$72.5\,keV$$ energy. X-rays emitted by the tube contain only

A. a continuous X-ray spectrum (Bremsstrahlung) with a minimum wavelength of $$0.155\mathop {\text{A}}\limits^ \circ $$

B. a continuous X-ray spectrum (Bremsstrahlung) with all wavelengths

C. the characteristic X-ray spectrum of tungsten

D. a continuous X-ray spectrum (Bremsstrahlung) with a minimum wavelength of $$0.155\mathop {\text{A}}\limits^ \circ $$ and the characteristic X-ray spectrum of tungsten.

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Releted Question 3

The intensity of X-rays from a Coolidge tube is plotted against wavelength $$\lambda $$ as shown in the figure. The minimum wavelength found is $${\lambda _C}$$ and the wavelength of the $${K_\alpha }$$ line is $${\lambda _K}.$$ As the accelerating voltage is increased

A. $${\lambda _K} - {\lambda _C}$$ increases

B. $${\lambda _K} - {\lambda _C}$$ decreases

C. $${\lambda _K}$$ increases

D. $${\lambda _K}$$ decreases

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Releted Question 4

The potential difference applied to an X-ray tube is $$5k\,V$$ and the current through it is 3.2$$mA.$$ Then the number of electrons striking the target per second is

A. $$2 \times {10^{16}}$$

B. $$5 \times {10^{6}}$$

C. $$1 \times {10^{17}}$$

D. $$4 \times {10^{15}}$$

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The anode voltage of a photocell is kept fixed. The wavelength $$\lambda $$ of the light falling on the cathode is gradually changed. The plate current $$I$$ of the photocell varies as follows

Releted MCQ Question on
Modern Physics >> Modern Physics Miscellaneous

The maximum kinetic energy of photoelectrons emitted from a surface when photons of energy $$6\,eV$$ fall on it is $$4\,eV.$$ The stopping potential, in volt, is

Electrons with energy $$80\,keV$$ are incident on the tungsten target of an X-ray tube. $$K$$-shell electrons of tungsten have $$72.5\,keV$$ energy. X-rays emitted by the tube contain only

The intensity of X-rays from a Coolidge tube is plotted against wavelength $$\lambda $$ as shown in the figure. The minimum wavelength found is $${\lambda _C}$$ and the wavelength of the $${K_\alpha }$$ line is $${\lambda _K}.$$ As the accelerating voltage is increased

The potential difference applied to an X-ray tube is $$5k\,V$$ and the current through it is 3.2$$mA.$$ Then the number of electrons striking the target per second is

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The anode voltage of a photocell is kept fixed. The wavelength $$\lambda $$ of the light falling on the cathode is gradually changed. The plate current $$I$$ of the photocell varies as follows

Releted MCQ Question on Modern Physics >> Modern Physics Miscellaneous

The maximum kinetic energy of photoelectrons emitted from a surface when photons of energy $$6\,eV$$ fall on it is $$4\,eV.$$ The stopping potential, in volt, is

Electrons with energy $$80\,keV$$ are incident on the tungsten target of an X-ray tube. $$K$$-shell electrons of tungsten have $$72.5\,keV$$ energy. X-rays emitted by the tube contain only

The intensity of X-rays from a Coolidge tube is plotted against wavelength $$\lambda $$ as shown in the figure. The minimum wavelength found is $${\lambda _C}$$ and the wavelength of the $${K_\alpha }$$ line is $${\lambda _K}.$$ As the accelerating voltage is increased

The potential difference applied to an X-ray tube is $$5k\,V$$ and the current through it is 3.2$$mA.$$ Then the number of electrons striking the target per second is

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