Tag: physics

Quizzes (598) Questions (13441)

Questions Related to physics

Multiple choice physics static electricity properties of charges charge properties of charge

The energy acquired by a charge of $8 \times 10 ^ { - 19 } { C }$ when passed through a potential difference of $200\ volt$

  1. $500 \mathrm { eV }$

  2. $1000 \mathrm { eV }$

  3. $1500 \mathrm { eV }$

  4. $2000 \mathrm { eV }$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$\begin{array}{l} U=qV \ =8\times { 10^{ -19 } }\times 200J \ =\dfrac { { 8\times { { 10 }^{ -19 } }\times 200 } }{ { 1.6\times { { 10 }^{ -19 } } } } eV \ =1000ev \ Hence,\, the\, option\, B\, is\, the\, correct\, answer. \end{array}$

Multiple choice physics static electricity properties of charges charge properties of charge

Two charges of equal magnitude and at a distance'r' exert a force $F$ on each other. If the charges are halved and distance between them is doubled, then the new force acting on each charge is

  1. $F / 8$

  2. $F / 4$

  3. $4 F$

  4. $F / 16$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Original force$,$

$F = k\dfrac{{q\,q}}{{{r^2}}}$
New force$,$
$F = k\dfrac{{\dfrac{q}{2}\,\dfrac{q}{2}}}{{{{\left( {2r} \right)}^2}}} = \dfrac{1}{{16}}F = \dfrac{F}{{16}}$
Hence,
option $(D)$ is correct answer. 

Multiple choice physics static electricity properties of charges charge properties of charge

Mark the correct options : 

  1. The total charge of the universe is constant.

  2. The total positive charge of the universe is constant.

  3. The total negative charge of the universe is constant.

  4. The total number of charged particles in the universe is constant.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The law of conservation of charges states that electric charge can neither be created nor destroyed.
Hence the net quantity of electric charge of the universe is always conserved. 

Multiple choice physics static electricity properties of charges charge properties of charge

$\displaystyle \frac {4}{25}$ Coulomb of charge contains .......... electrons

  1. $10^{15}$

  2. $10^{18}$

  3. $10^{20}$

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The formula for quantization of charge is given as q=ne.
where q is the amount of charge in Columbu's, n is the number of charges and e is the charge on the electron.
In this case, q=4/25 C
So, e = $1.6\times { 10 }^{ -19 }C$.
n can be calculated as n=q/e = $\frac { 4 }{ 25 } \times [\dfrac { 1 }{ 1.6\times { 10 }^{ -19 }C } ]\quad =\quad { 10 }^{ 18 }$ which is the number of electrons.
Hence, 4/25 Coulomb of charge contains ${ 10 }^{ 18 }$ electrons.

Multiple choice physics static electricity properties of charges charge properties of charge

The conservation of electric charge implies that

  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
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
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

Multiple choice physics static electricity properties of charges charge properties of charge

The number of electrons for one coulomb of charge are:

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

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

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

  4. $\displaystyle 6.25\times { 10 }^{ 19 }$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

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

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

Multiple choice physics static electricity properties of charges charge properties of charge

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

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

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

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

  4. $\displaystyle 5.25\times { 10 }^{ 14 }$
Reveal answer Fill a bubble to check yourself
A Correct answer
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}$

Multiple choice physics static electricity properties of charges charge properties of charge

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

  1. decrease

  2. increase

  3. remain constant

  4. none
Reveal answer Fill a bubble to check yourself
B Correct answer
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.