The ratio of coulomb's electrostatic force to the gravitational force between an electron and a proton separated by some distance is \(2.4\times 10^{39}\). The ratio of the proportionality constant, \(K=\frac{1}{4\pi\varepsilon_0}\) to the gravitational constant \(G\) is nearly:

(Given that the charge of the proton and electron each \(=1.6\times 10^{-19}\), the mass of the electron = \(9.11\times 10^{-31}\) kg, the mass of the proton \(=1.67\times 10^{-27}\) kg):

(Given that the charge of the proton and electron each \(=1.6\times 10^{-19}\), the mass of the electron = \(9.11\times 10^{-31}\) kg, the mass of the proton \(=1.67\times 10^{-27}\) kg):

1. | \(10^{20}\) | 2. | \(10^{30}\) |

3. | \(10^{40}\) | 4. | \(10\) |

Subtopic: Coulomb's Law |

60%

From NCERT

NEET - 2022

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The acceleration of an electron due to the mutual attraction between the electron and a proton when they are \(1.6~\mathring{A}\) apart is:

( **\(\frac{1}{4 \pi \varepsilon_0}=9 \times 10^9~ \text{Nm}^2 \text{C}^{-2}\)** )

1. | \( 10^{24} ~\text{m/s}^2\) | 2 | \( 10^{23} ~\text{m/s}^2\) |

3. | \( 10^{22}~\text{m/s}^2\) | 4. | \( 10^{25} ~\text{m/s}^2\) |

Subtopic: Coulomb's Law |

75%

From NCERT

NEET - 2020

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Two point charges \(A\) and \(B\), having charges \(+Q\) and \(-Q\) respectively, are placed at a certain distance apart and the force acting between them is \(F.\) If \(25\%\) charge of \(A\) is transferred to \(B\), then the force between the charges becomes:

1. | \(\frac{4F}{3}\) | 2. | \(F\) |

3. | \(\frac{9F}{16}\) | 4. | \(\frac{16F}{9}\) |

Subtopic: Coulomb's Law |

76%

From NCERT

NEET - 2019

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Suppose the charge of a proton and an electron differ slightly. One of them is \(-e\), the other is (\(e+\Delta e\)). If the net of electrostatic force and gravitational force between two hydrogen atoms placed at a distance \(d\) (much greater than atomic size) apart is zero, then$$ \(\Delta e\) is of the order of? (Given mass of hydrogen ${\mathrm{}}_{}$\(m_h = 1.67\times 10^{-27}~\text{kg}\)$$)

1. \(10^{-23}~\text{C}\)

2. \(10^{-37}~\text{C}\)

3. \(10^{-47}~\text{C}\)

4. \(10^{-20}~\text{C}\)

Subtopic: Coulomb's Law |

65%

From NCERT

NEET - 2017

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Two identical charged spheres suspended from a common point by two massless strings of lengths \(l,\) are initially at a distance \(d\) \(\left ( d\ll l \right )\) apart because of their mutual repulsion. The charges begin to leak from both the spheres at a constant rate. As a result, the spheres approach each other with a velocity \(v.\) Then, \(v\) varies as a function of the distance \(x\) between the sphere, as:

1. \(v\propto x\)

2. \(v\propto x^{-1/2}\)

3. \(v\propto x^{-1}\)

4. \(v\propto x^{1/2}\)

1. \(v\propto x\)

2. \(v\propto x^{-1/2}\)

3. \(v\propto x^{-1}\)

4. \(v\propto x^{1/2}\)

Subtopic: Coulomb's Law |

78%

From NCERT

NEET - 2016

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Two pith balls carrying equal charges are suspended from a common point by strings of equal length, the equilibrium separation between them is \(r\) (as shown in Fig. I). Now, as shown in Fig. II, the strings are rigidly clamped at half the height. The equilibrium separation between the balls now becomes:

1. \(\frac{r}{\sqrt[3]{2}}\)

2. \(\frac{r}{\sqrt[2]{2}}\)

3. \(\frac{2r}{3}\)

4. none of the above

1. \(\frac{r}{\sqrt[3]{2}}\)

2. \(\frac{r}{\sqrt[2]{2}}\)

3. \(\frac{2r}{3}\)

4. none of the above

Subtopic: Coulomb's Law |

70%

From NCERT

AIPMT - 2013

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Two positive ions, each carrying a charge q, are separated by a distance d. If F is the force of repulsion between the ions, the number of electrons missing from each ion will be:

(e is the charge on an electron)

1. $\frac{4\pi {\epsilon}_{0}F{d}^{2}}{{e}^{2}}$

2. $\sqrt{\frac{4\pi {\epsilon}_{0}F{d}^{2}}{{d}^{2}}}$

3. $\sqrt{\frac{4\pi {\epsilon}_{0}F{d}^{2}}{{e}^{2}}}$

4. $\frac{4\pi {\epsilon}_{0}F{d}^{2}}{{q}^{2}}$

Subtopic: Coulomb's Law |

77%

From NCERT

AIPMT - 2010

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The unit of permittivity of free space ε_{0} is:

1. | Newton metre^{2} / Coulomb^{2} |

2. | Coulomb^{2} /Newton metre^{2} |

3. | Coulomb^{2}/ (Newton metre)^{2} |

4. | Coulomb/Newton metre |

Subtopic: Coulomb's Law |

72%

From NCERT

AIPMT - 2004

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