SATHEE: Electrostatics Question 238

Electrostatics Question 238

Question: A negatively charged plate has charge density of $2 \times 10^{- 6} C / m^{2}$ . The initial distance of an electron which is moving toward plate, cannot strike the plate, if it is having energy of $200 e V$ [RPET 1997]

Options:

A) Periodic for all values of $z_{0}$ satisfying $0 < z_{0} < \infty$

B) Simple harmonic for all values of satisfying $0 < z_{0} < R$

C) Approximately simple harmonic provided $z_{0} « R$

D) Such that $P$ crosses $O$ and continues to move along the negative $z -$ axis towards $z = - \infty$

Show Answer

Answer:

Correct Answer: A , C

Solution:

Here $E = \frac{1}{4 π ε_{0}} . \frac{Q z_{0}}{{(R^{2} + z_{0}^{2})}^{3 / 2}}$ where Q is the charge on ring and $z_{0}$ is the distance of the point from origin. Then $F = q E = \frac{- Q q z_{0}}{4 π ε_{0} {(R^{2} + z_{0}^{2})}^{3 / 2}}$ When charge -q crosses origin, force is again towards centre i.e., motion is periodic. Now if $z_{0} « R$ $F = - \frac{1}{4 π ε_{0}} . \frac{Q q z_{0}}{R^{2}}$

therefore $F \propto - z_{0}$ i.e., motion is S.H.M.

Electrostatics Question 238

Question: A negatively charged plate has charge density of $2 \times 10^{- 6} C / m^{2}$ . The initial distance of an electron which is moving toward plate, cannot strike the plate, if it is having energy of $200 e V$ [RPET 1997]

Options:

Answer:

Solution:

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Electrostatics Question 238

Question: A negatively charged plate has charge density of 2×10−6C/m2 . The initial distance of an electron which is moving toward plate, cannot strike the plate, if it is having energy of 200eV [RPET 1997]

Options:

Answer:

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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Question: A negatively charged plate has charge density of $2 \times 10^{- 6} C / m^{2}$ . The initial distance of an electron which is moving toward plate, cannot strike the plate, if it is having energy of $200 e V$ [RPET 1997]