Question icon
Grade 11Electric Current

Two pitch balls each of mass 1g and carrying a charge of 1 mC are attached to the ends of silk threads 1 m

long, the other ends of which are attached to some fixed point, in a gravity free space. The force between

them is

(a) 9.8´ 10-6 N (b) 9.8 ´ 10-12 N (c) 2.25 ´ 10-3 N (d) 4.5 ´ 10-6 N

Profile image of jeet jeetu
13 Years agoGrade 11
Answers icon

1 Answer

Profile image of Askiitians Tutor Team
ApprovedApproved Tutor Answer1 Year ago

To determine the force between the two charged pitch balls, we can use Coulomb's Law, which describes the electrostatic force between two point charges. The formula is given by:

Coulomb's Law

The equation for Coulomb's Law is:

F = k * |q1 * q2| / r²

Where:

  • F is the force between the charges.
  • k is Coulomb's constant, approximately 8.99 × 10^9 N m²/C².
  • q1 and q2 are the magnitudes of the charges.
  • r is the distance between the centers of the two charges.

Given Values

In this scenario:

  • Mass of each ball, m = 1 g = 0.001 kg (though mass is not needed for calculating the electrostatic force).
  • Charge of each ball, q1 = q2 = 1 mC = 1 × 10^-3 C.
  • Distance between the charges, r = 1 m (length of the silk thread).

Calculating the Force

Now, substituting the values into Coulomb's Law:

F = (8.99 × 10^9 N m²/C²) * |(1 × 10^-3 C) * (1 × 10^-3 C)| / (1 m)²

Calculating the numerator:

F = (8.99 × 10^9) * (1 × 10^-6) / 1

F = 8.99 × 10^3 N

Now, converting this to a more manageable form:

F = 8.99 × 10^3 N = 8.99 × 10^6 μN

Final Result

Since we need to express the force in terms of micro-Newtons (μN), we can convert:

F = 8.99 × 10^6 μN

However, this value does not match any of the options provided. Let's double-check the calculations and the units:

It appears that the initial charge values and the distance were correctly applied. The force calculated is significantly larger than the options given, indicating a potential misunderstanding in the problem setup or the values provided.

In conclusion, based on the calculations using Coulomb's Law, the force between the two charged pitch balls is approximately 8.99 × 10^6 μN, which does not correspond to any of the answer choices listed. If you have further details or constraints regarding the problem, please share them for a more accurate assessment.