Tag: properties of charge

Questions Related to properties of charge

A spherical metal shell $A$ of radius ${R} _{A}$ and a solid metal sphere $B$ of radius ${R} _{8}\left( <{ R } _{ A } \right)$ are kept far apart and each is given charge $+Q$. Now they are connected by a thin metal wire. Then 

physics static electricity properties of charges charge properties of charge

  1. ${ E } _{ A }^{ inside }=0$

  2. $\quad { Q } _{ A }>{ Q } _{ B }$

  3. $\dfrac { { \sigma } _{ A } }{ { \sigma } _{ B } } =\dfrac { { R } _{ B } }{ R _{ A } }$

  4. ${ E } _{ A }^{ on\quad surface }<{ E } _{ B }^{ on\quad surface }$

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Correct Option: A,B,C,D
Explanation:
Electric field inside a spherical metallic shell with charge on surface $=0$
$\therefore (a)$ is correct
On connecting Both with wise
Electric potential will be equal say $V$
$\therefore \dfrac{1}{4\pi Co}\dfrac{Q _A}{R _A}=\dfrac{1}{4\pi Co}\dfrac{Q _B}{R _B}=V$
as $R _A> R _B\therefore Q _A > Q _B$ Hence $(b)$ is correct
as $\dfrac{\sigma _A}{\sigma _B}=\dfrac{Q _B}{4\pi R _{B}^{2}}=\dfrac{R^{2}B}{R^{2}A}\times \dfrac{4\pi Co R _{A}V}{4\pi Co R _{A}R}$
$\dfrac{\sigma A}{\sigma B}=\dfrac{R _B}{R _A}$             $(C)$ is correct
Also $E _{A}=\dfrac{\sigma _A}{\sigma _B}=\dfrac{R _B}{R _A}<1\therefore E _A < E _B$
Hence $(d)$ is correct

Electron accelerated by potential $V$ are diffracted from a crystal. If $d=1 A$ and $i = 30^\circ $. $V$ should be about  $h = 6.6 \times {10^{ - 24}}Js\,{m _e} = 9.1 \times {10^{ - 33}}kg.e = 1.6 \times {10^{ - 19}}C$

physics static electricity properties of charges charge properties of charge

  1. $2000 V$

  2. $50 V$

  3. $500 V$

  4. $1000 V$

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Correct Option: B
Explanation:

$d=1A$

$i={ 30 }^{ o  }$
$\theta ={ 60 }^{ o  }$
$h=6.6\times { 10 }^{ -34 }Js$
${ m } _{ e }=9.1\times { 10 }^{ -31 }kg$
$e=1.6\times { 10 }^{ -19 }c$
$n\lambda =2dsin\theta $
$\lambda =\dfrac { 2\times 1A\times sin{ 60 }^{ o  } }{ 1 } $
$\lambda =\sqrt { 3A } $
$\sqrt { V } =\dfrac { 1.27\times { 10 }^{ -10 } }{ \sqrt { 3 } \times { 10 }^{ -10 } } =50.18volts$

All free electric charges can be 
($e=$ single unit of charge i.e. the magnitude of charge on electron )

physics static electricity properties of charges charge properties of charge

  1. odd multiples of $e$

  2. fractional multiples of $e$

  3. even multiples of $e$

  4. negative multiples of $e$

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Correct Option: A,C,D
Explanation:

Charges are acquired by either gain or loss of electrons .

And electron transfer can occur only in form of integers, fraction of electron can't be shared.

Hence, charge on a body can be positive or negative integral multiple of $e$.

Answer-(A),(C),(D)

Charge $q$ on a body in terms of transfer of electrons can be expressed as
( $n=$ net number of electrons transacted)

physics static electricity properties of charges charge properties of charge

  1. $ q = ne$

  2. $ q = \dfrac{e}{n}$

  3. $ q = - \dfrac{e}{n}$

  4. None of these

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Correct Option: A
Explanation:

Charge on each electron$=e$


If  n be the number of electrons transferred, then charge $q=ne$.

Answer-(B)