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Electric Charges And Fields

Q: Complete the following statements with an appropriate word /term be filled in the blank space(s).The force of attraction or repulsion between two charges is given by ......................

Coulomb's law: The force exerted by one point charge is proportional to the product of the charge and varies inversely as the sure of the distance separating the charges.

Q: The ampere-sec stands for the unit of :

Charge is given by the relation, \$q = I*t\$so its unit is ampere - sec

Q: Electroscope is an instrument used to find the quantity of charge on different bodies.

Electroscope is an instrument used to measure the amount of charge on a body.Hence, given statement is \$True\$.

Q: Two unlike charges attract each other with a force of 10N. If the distance between them is doubled, the force between them is :

We know \$F=\dfrac {1}{4\pi \varepsilon_0}\dfrac {q_1q_2}{r^2}=10 N\$if distance is doubled.\$F_{new}=\dfrac {1}{4\pi \varepsilon_0}\cdot \dfrac {q_1q_2}{(2r)^2}=\dfrac {10}{4}\$\$=2\cdot 5 N\$

Q: Number of electric lines of force emanating from \$1C\$ of positive charge in vacuum is :

\$\phi \$ from \$1C \$ of charge is \$= \dfrac{Q_{enclosed}}{\epsilon_o}\$\$= \dfrac{1}{8.8501\times 10^{-12}}\$\$= 1.129\times 10^{11}\$

Q: A force ‘F’ is acting between two charges in air. If the space between them be completely filled with a medium \$K=4\$, the force will be :

By Coulomb's law, the force between two charges \$(q_1, q_2)\$ in air is given by \$F=\dfrac{q_1q_2}{4\pi\epsilon_0 r^2}\$ where \$r=\$ distance between two charges.Now the force between two charges \$(q_1, q_2)\$ in medium with dielectric constant \$K=4\$ becomes, \$F'=\dfrac{q_1q_2}{4\pi K\epsilon_0 r^2}\$So, \$F'=\dfrac{F}{K}=\dfrac{F}{4}\$

Q: A charge \$q_1\$ exerts a force of \$45N\$ on a charge of \$q_{2}=10^{-5} C\$ located at a point \$0.2m\$ from \$q_{1}\$. The magnitude of \$q_{1}\$ is

As we know electrostatic force between two charges \$F=\dfrac {k q_1 q_2}{r^2}\$\$\Rightarrow 45=\dfrac {(9\times 10^9)(q_1)(10^{-5})}{(0\cdot 2)^2}\$\$\Rightarrow q_1=\dfrac {45\times 0\cdot 2\times 0\cdot 2}{9\times 10^9\times 10^{-5}}\$\$\Rightarrow q_1=2\times 10^{-5}C\$

Q: Two point charges \$2\ C\$ and \$-6\ C\$ attract each other with a force of \$12\ N\$. A negative charge of \$2\ C\$ is added to each of the above charges, now the force between them is :

When \$-2C\$ is added to \$2C\$ and \$-6C\$, they become \$0C\$ and \$-8C\$ respectively. Since one of the charges is now zero, the force between them is zero.

Q: An electron revolves around the nucleus of hydrogen atom in a circle of radius \$5\times 10^{-11}\ m\$. The intensity of electric field at a point in the orbit of the electron is:

We know hydrogen atom consist of one proton and one electron\$R=5\times 10^{-11} m\$We know attractive force \$=\dfrac {k q_1(q_2)}{r^2}=\dfrac {9\times 10^9\times (1\cdot 6\times 10^{-19})^2}{(5\times 10^{-11})^2}\$We know \$F = E q\$\$\therefore E=\dfrac {F}{q}\$\$\therefore E=\dfrac {9\times 10^9\times (1\cdot 6\times 10^{-19})}{5\times 10^{-11})^2}=5\cdot 76\times 10^{11} N/C.\$

Physics
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Complete the following statements with an appropriate word /term be filled in the blank space(s).

The force of attraction or repulsion between two charges is given by ......................

Gauss's law

Kepler's law

Coulomb's law

Gravitational law

Easy

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The ampere-sec stands for the unit of :

Power

Current

Energy

Charge

Easy

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Electroscope is an instrument used to find the quantity of charge on different bodies.

True

False

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Two unlike charges attract each other with a force of 10N. If the distance between them is doubled, the force between them is :

40 N

20 N

5 N

2.5 N

Easy

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Number of electric lines of force emanating from $1 C$ of positive charge in vacuum is :

8.85 \times 1 0^{- 12}

9 \times 1 0^{9}

1 / 4 π \times 9 \times 1 0^{9}

1.13 \times 1 0^{11}

Easy

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A force ‘F’ is acting between two charges in air. If the space between them be completely filled with a medium $K = 4$ , the force will be :

F

4 F

\frac{F}{4}

2 F

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A charge $q_{1}$ exerts a force of $45 N$ on a charge of $q_{2} = 1 0^{- 5} C$ located at a point $0.2 m$ from $q_{1}$ . The magnitude of $q_{1}$ is

4 \times 1 0^{- 8} C

2 \times 1 0^{- 5} C

3 \times 1 0^{- 6} C

5 \times 1 0^{- 8} C

Easy

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When we remove polyester or woollen clothes in dark, we can see a spark and hear a crackling sound. Which of the following is responsible for it?

Static electricity.

Current electricity.

Reflection of light.

Refraction of light.

Easy

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Two point charges $2 C$ and $- 6 C$ attract each other with a force of $12 N$ . A negative charge of $2 C$ is added to each of the above charges, now the force between them is :

32 N

8 N

z e r o

4 N

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An electron revolves around the nucleus of hydrogen atom in a circle of radius $5 \times 1 0^{- 11} m$ . The intensity of electric field at a point in the orbit of the electron is:

5.76 \times 1 0^{11} N / C

9.216 \times 1 0^{- 8} N / C

0

4 N / C

Easy

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Electric Charges And Fields

Physics 26031 Views

Complete the following statements with an appropriate word /term be filled in the blank space(s). The force of attraction or repulsion between two charges is given by ......................

The ampere-sec stands for the unit of :

Electroscope is an instrument used to find the quantity of charge on different bodies.

Two unlike charges attract each other with a force of 10N. If the distance between them is doubled, the force between them is :

Number of electric lines of force emanating from 1C of positive charge in vacuum is :

A force ‘F’ is acting between two charges in air. If the space between them be completely filled with a medium K=4, the force will be :

A charge q1​ exerts a force of 45N on a charge of q2​=10−5C located at a point 0.2m from q1​. The magnitude of q1​ is

When we remove polyester or woollen clothes in dark, we can see a spark and hear a crackling sound. Which of the following is responsible for it?

Two point charges 2 C and −6 C attract each other with a force of 12 N. A negative charge of 2 C is added to each of the above charges, now the force between them is :

An electron revolves around the nucleus of hydrogen atom in a circle of radius 5×10−11 m. The intensity of electric field at a point in the orbit of the electron is:

Physics
26031 Views

Complete the following statements with an appropriate word /term be filled in the blank space(s).

The force of attraction or repulsion between two charges is given by ......................

Number of electric lines of force emanating from $1 C$ of positive charge in vacuum is :

A force ‘F’ is acting between two charges in air. If the space between them be completely filled with a medium $K = 4$ , the force will be :

A charge $q_{1}$ exerts a force of $45 N$ on a charge of $q_{2} = 1 0^{- 5} C$ located at a point $0.2 m$ from $q_{1}$ . The magnitude of $q_{1}$ is

Two point charges $2 C$ and $- 6 C$ attract each other with a force of $12 N$ . A negative charge of $2 C$ is added to each of the above charges, now the force between them is :

An electron revolves around the nucleus of hydrogen atom in a circle of radius $5 \times 1 0^{- 11} m$ . The intensity of electric field at a point in the orbit of the electron is: