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  • I have a doubt, kindly clarify. Two identical charged spheres are suspended by strings of equal lengths. The strings make an angle of 300 with each other. When suspended in a liquid of density 0.8 g cm-3 , the angle remains the same. If density of th

Two identical charged spheres are suspended by strings of equal lengths. The strings make an angle of 300 with each other. When suspended in a liquid of density 0.8 g cm-3 , the angle remains the same. If density of the material of the sphere is 1.6 g cm-3, the dielectric constant of the liquid is

  • Option 1)

    1

  • Option 2)

    4

  • Option 3)

    3

  • Option 4)

    2

 

Answers (5)

best_answer

As we leant in

Coulombic force -

F\propto Q_{1}Q_{2}=F\propto \frac{Q_{1}Q_{2}}{r^{2}}=F=\frac{KQ_{1}Q_{2}}{r^{2}}

- wherein

K - proportionality Constant 

Q1 and Q2 are two Point charge

 

  T\cos \Theta=mg --(i)

T\sin \Theta=F_{e} --(ii)

\therefore from equation (i) & (ii)

Tan \Theta=\frac{F_{e}}{mg}---(iii)

if ball is suspended in liquid g'=g[1-\frac{\sigma }{\rho }]

Tan \Theta'=\frac{F'_{e}}{mg'}

=\frac{f}{kmg(1-\frac{\sigma}{\rho })} --(iv)

According to question     \Theta'=\Theta

from equation (iv) & (iii)

K=\frac{1}{1-\frac{\sigma }{\rho }}

=\frac{\rho }{(\rho -\sigma )} =\frac{1.6}{(1.6-0.8)}=2

\Rightarrow    K=2

 

 

 

 


Option 1)

1

This is incorrect option

Option 2)

4

This is incorrect option

Option 3)

3

This is incorrect option

Option 4)

2

This is correct option

Posted by

prateek

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Option (4)

Posted by

Sneha s p

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Right answers-3

Posted by

ATAR SINGH

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Answer is 2 of option 4

 

Posted by

Aditya

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