Coulomb's law for electrostatic force between two point charges


Asked by admin @ in Physics viewed by 304 People


Coulombs' law for electrostatic force between two point charges and Newton's law for gravitational force between two stationary point masses, both have inverse-square dependence on the distance between the charges/masses.

(a) Compare the strength of these forces by determining the ratio of their magnitude
(i) for an electron and a proton and (ii) for two protons.
(b) Estimate the accelerations for electron and proton due to the electrical force of their mutual attraction when they are 1Å (= 10−10 m) apart? mp = 1.67 ✕ 10−27 kg m e = 9.11 ✕ 10−31 kg.

Answered by admin @



We know

charge of an electron = -1.67 ×10⁻¹⁹ C  

charge of an proton = 1.67 ×10⁻¹⁹ C

Mass of electron = 9.1 × 10⁻³¹ kg

Mass of proton = 1.67 × 10⁻²⁷ kg

(a). (i)

(Coulomb force/Gravitational force)

= {(9 ×10⁹×(-1.6×10⁻¹⁹)1.6×10⁻¹⁹)/r²}/{(6.67×10⁻¹¹×9.1×10⁻³¹×1.67×10⁻²⁷)/r²}  

= 23.04×10⁻²⁹/101.36×10⁻⁶⁹

= 0.2273×10⁻⁴⁰

=2.27×10⁻³⁹

(ii)(Coulomb force/Gravitational force)

= {(9×10⁹×(1.6×10⁻²⁹)²/r²)}/{6.67×10⁻¹¹×(1.67×10⁻²⁷)²/r²}

=1.24×10³⁶

(b)

Force F = 9×10⁹(-1.6×10⁻¹⁹)×1.6×10⁻¹⁹/(10⁻¹⁰)²

F = 2.304 × 10⁻⁸ N

And we know Force F = mass × acceleration

Hence acceleration of electron = F/m =  2.304 × 10⁻⁸ N/ 9.1 × 10⁻³¹ kg

a₁ = 2.5 × 10²² m/s²

and acceleration of proton a₂ = 2.304 × 10⁻⁸ N/1.67 × 10⁻²⁷ kg

a₂ = 1.4 × 10¹⁹ m/s²


Similar Questions

The force between two charged bodies is called

Asked by admin @ in Physics viewed by 318 persons

The force between two charged body is called which force option A electrostatics B magnetic force C gravitational D muscular

State the law of attraction and repulsion between electrostatic charges

Asked by admin @ in Physics viewed by 289 persons

State the law of electrostatic force of attraction and repulsion​

Two point charges a and b having charges

Asked by admin @ in Physics viewed by 329 persons

74. Two point charges A and B, having charges+Q and -Q respectively, are placed at certaindistance apart and force acting between them isF. If 25% charge of …

Two point charges 2c and 6c repel each other

Asked by admin @ in Physics viewed by 280 persons

2 point charges +2C +6C repel each other with a force of 12N . If a charge q is given to each of these charges then they attract with 4N. …

Two point charges of 20 microcoulomb and 80 microcoulomb

Asked by admin @ in Physics viewed by 361 persons

Two point charges 20 microcoulomb and 80 microcoulomb are 10 cm apart at which point on the line joining them electric field will be zero

Two point electric charges of values q and 2q

Asked by admin @ in Physics viewed by 312 persons

⦁ Two point charges of values ‘q’ and ‘2q’ are kept at a distance ‘d’ apart from each other in air. A third charge ‘Q’ is to be kept along …

The sum of two point charges is 7 microcoulomb

Asked by admin @ in Physics viewed by 329 persons

The sum of two point charges is 7 micro Coulomb. They repel each other with a force of 1N when kept 30cm apart in free space. Calculate the value of …

Two point charges qa 3uc and qb 3uc

Asked by admin @ in Physics viewed by 322 persons

Question 1.8: Two point charges qA = 3 μC and qB = −3 μC are located 20 cm apart in vacuum. (a) What is the electric field at the midpoint …

Two point charges q1 and q2 are 3m apart

Asked by admin @ in Physics viewed by 280 persons

Two point charges Q1 and Q2 are 3m apart and the sum of charges is 10C. then find the values of Q1 and Q2 ​

What is the force between two small charged spheres

Asked by admin @ in Physics viewed by 299 persons

Question 1.1: What is the force between two small charged spheres having charges of 2 × 10 −7 C and 3 × 10 −7 C placed 30 cm apart in …

Ratio of electrostatic force to gravitational force between two electrons

Asked by admin @ in Physics viewed by 357 persons

The ratio of electrostatic force between two electrons to gravitation force between them is of the orderA) 10C) 10^3B)1D) 10^42​

Electric lines of force about negative point charge are

Asked by admin @ in Physics viewed by 311 persons

Electric lines of force about a negative point charge are (a) circular anticlockwise (b) circular clockwise (c) radial, inwards (d) radial, outwards

Two point charges placed at a distance r

Asked by admin @ in Physics viewed by 366 persons

Two point charges placed at a certain distance r in air exert a force F on each other. Then the distance R at which these charges will exert the same …

Two identical point charges q each are kept 2m

Asked by admin @ in Physics viewed by 386 persons

Two identical point charges q each are kept 2m apart in air. A third point charges Q of unknown magnitude and sign is placed on the line joining the charges …

The electrostatic force of repulsion between two positive ions

Asked by admin @ in Physics viewed by 335 persons

The electrostatic force of repulsion between two positively charged ions carrying equal charges is 3.7*10^-9 N , when they are separated by distance of 5 Amg. How many electrons are …

Most viewed questions in Physics


Jeevandeep health and physical education std 10 answers pdf

Asked by admin @ in Physics viewed by 11074 persons


Hc verma physics class 9 solutions of describing motion

Asked by admin @ in Physics viewed by 2673 persons


How to leave nightmare land answer key

Asked by maham237 @ in Physics viewed by 1599 persons



Base area and stability of some objects with different shapes

Asked by admin @ in Physics viewed by 1533 persons


Which of the following statements about safe lifting are correct

Asked by admin @ in Physics viewed by 1518 persons


Porous water-absorbing mass of fibers

Asked by wiki @ in Physics viewed by 1497 persons



Absorption of water by filter paper is due to

Asked by admin @ in Physics viewed by 1440 persons


A composite wire of uniform diameter 3mm

Asked by admin @ in Physics viewed by 1407 persons


At a distance l 400m from the traffic light

Asked by admin @ in Physics viewed by 1338 persons



A rocket of mass m is launched straight up with thrust f⃗ thrust.

Asked by maham237 @ in Physics viewed by 1318 persons


Mind map for light reflection and refraction class 10

Asked by admin @ in Physics viewed by 1150 persons



A thief runs at a speed of 10m s

Asked by admin @ in Physics viewed by 1098 persons


A 5.8 x 10 4 watt elevator motor can lift

Asked by maham237 @ in Physics viewed by 1082 persons