SATHEE: Modern Physics 2 Question 28

Modern Physics 2 Question 28

27. A silver sphere of radius $1 c m$ and work function $4.7 e V$ is suspended from an insulating thread in free-space. It is under continuous illumination of $200 n m$ wavelength light. As photoelectrons are emitted, the sphere gets charged and acquires a potential. The maximum number of photoelectrons emitted from the sphere is $A \times 10^{Z}$ (where $1 < A < 10$ ). The value of $Z$ is

(2011)

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Solution:

Photo emission will stop when potential on silver sphere becomes equal to the stopping potential.

$\begin{aligned} ∴ \frac{h c}{λ} - W = e V_{0} \\ Here, V_{0} = \frac{1}{4 π ε_{0}} \frac{z e}{r} \\ ∴ \frac{1240}{200} e V - (4.7 e V) = \frac{9 \times 10^{9} \times n \times 1.6 \times 10^{- 19}}{10^{- 2}} \\ (6.2 - 4.7) = \frac{9 \times 10^{9} \times n \times 1.6 \times 10^{- 19}}{10^{- 2}} \\ or z = \frac{1.5 \times 10^{- 2}}{9 \times 1.6 \times 10^{- 10}} \\ = 1.04 \times 10^{7} \end{aligned}$

$∴$ Answer is 7 .

Modern Physics 2 Question 28

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Modern Physics 2 Question 28

Fill in the Blank

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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