Tag: properties of charge

Questions Related to properties of charge

The conservation of electric charge implies that

physics static electricity properties of charges charge properties of charge

  1. charge cannot be created

  2. charge cannot be destroyed

  3. the number of charged particles in the universe is constant

  4. simultaneous creation of equal and opposite charges is permissible

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Correct Option: A,B,C
Explanation:

A, B and C are correct. 

A substance is neutral due to the presence of equal magnitude of positive and negative charge on it.
Although D is possible in radioactivity and its reactions, it is not related to the statement of the question

The number of electrons for one coulomb of charge are:

physics static electricity properties of charges charge properties of charge

  1. $\displaystyle 6.25\times { 10 }^{ 23 }$

  2. $\displaystyle 6.25\times { 10 }^{ 21 }$

  3. $\displaystyle 6.25\times { 10 }^{ 18 }$

  4. $\displaystyle 6.25\times { 10 }^{ 19 }$

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Correct Option: C
Explanation:

1 electron carries a charge of $1.6 \times 10^{-19}$ coulomb 

So, No.of electron in one coulomb
$\dfrac{1}{1.6 \times 10^{-19}} = \dfrac{10^{19}}{1.6} = 6.25 \times 10^{18}$

How many electrons make up a charge of $\displaystyle 20\mu C$ ?

physics static electricity properties of charges charge properties of charge

  1. $\displaystyle 1.25\times { 10 }^{ 14 }$

  2. $\displaystyle 2.23\times { 10 }^{ 14 }$

  3. $\displaystyle 3.25\times { 10 }^{ 14 }$

  4. $\displaystyle 5.25\times { 10 }^{ 14 }$

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Correct Option: A
Explanation:

Charge on an electron $= 1.6 \times 10^{-19}$coulomb

no of electrons required $ = \dfrac{20 \times 10^{-6}}{1.6 \times 10^{-19}} = 1.25 \times 10^{14}$

When resistance element of a heater fuses and then we reconnect it after removing a portion of it, the power of the heater will :

physics static electricity properties of charges charge properties of charge

  1. decrease

  2. increase

  3. remain constant

  4. none

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Correct Option: B
Explanation:

When ressitance element of a heater fuses and then we reconnect it after removing a portion of it, the power of the heater will increases because the resistance of wire decreases due to decrease in length of it. 


Option B is correct.

Sparking occurs when a load is switched off because the circuit has high :

physics static electricity properties of charges charge properties of charge

  1. resistance

  2. inductance

  3. capacitance

  4. impedance

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Correct Option: B
Explanation:

When circuit has high inductance then sparking occurs.


Option B is correct.


When electric current passes through a bucket full of water , lot of bubbling is observed. This suggests that the type of supply is

physics static electricity properties of charges charge properties of charge

  1. AC

  2. DC

  3. any of the above two

  4. None of the above

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Correct Option: B
Explanation:

When a dc current is passed through water, the electrolysis of water molecules $(H _{2}O)$ takes place i.e, water gets split into hydrogen and oxygen gases. The bubbles are these gases escaping.

How many electronic charges from $1$ coulomb?

physics static electricity properties of charges charge properties of charge

  1. $9.1\times 10^{-31}$

  2. $1.6\times 10^{18}$

  3. $62.5\times 10^{17}$

  4. $1.76\times 10^{11}$

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Correct Option: C
Explanation:

Let the total electronic charge be n

$1=ne=n\times 1.6\times 10^{-19}$
$n=62.5\times 10^{17}$

The net charge inside an isolated system is

physics static electricity properties of charges charge properties of charge

  1. conserved

  2. variable

  3. zero

  4. infinite.

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Correct Option: A
Explanation:

According to law of conservation of charge, the net charge inside an isolated system is conserved. 

A charge of $-1C$ contains $n$ electrons, then $n=?$

physics static electricity properties of charges charge properties of charge

  1. $6.25 \times 10^{-20}$

  2. $6.25 \times 10^{19}$

  3. $6.25 \times 10^{18}$

  4. $6.25 \times 10^{-19}$

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Correct Option: C
Explanation:

Here, $n(-e)=Q=-1C$ or $n=1/e=\dfrac{1}{(1.6\times 10^{-19})}=6.25\times 10^{18}$

If $Q _1 = 5\mu C$, $Q _2 = 3 \mu C$ and $Q _3= -2 \mu C$, then the net charge in the system is :

physics static electricity properties of charges charge properties of charge

  1. $-6 \mu C$

  2. $6 \mu C$

  3. $8 \mu C$

  4. $-2 \mu C$

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Correct Option: B
Explanation:

The net charge of the given system is $Q=Q _1+Q _2+Q _3=(5+3-2)\mu C=6\mu C$