The force acting between two point charges kept at a certain distance ...
Its b 4phy
F=kQ2/r2=phy/4
r2=kQ2×4/phy
when Q is dounled and distance is halved
f=k4×Q2 ×phy×4/kQ2×4
f=4phy
The force acting between two point charges kept at a certain distance ...
Given:
- Force between two point charges at a certain distance = phy/4
To find:
- Force between the same charges when charge magnitudes are doubled and distance is halved.
Solution:
Step 1: Understanding the given scenario
- Let's assume the two point charges as q1 and q2.
- The force between the charges is given by Coulomb's law: F = k * (q1 * q2) / r^2, where F is the force, k is the electrostatic constant, q1 and q2 are the magnitudes of the charges, and r is the distance between them.
- Given that the force is phy/4, we can write the equation as phy/4 = k * (q1 * q2) / r^2.
Step 2: Doubling the charge magnitudes and halving the distance
- Now, let's double the magnitudes of the charges: q1' = 2q1 and q2' = 2q2.
- Also, let's halve the distance between the charges: r' = r/2.
Step 3: Finding the new force
- Using Coulomb's law with the new magnitudes and distance, the force can be calculated as: F' = k * (q1' * q2') / r'^2.
- Substituting the values: F' = k * (2q1 * 2q2) / (r/2)^2 = (4 * k * q1 * q2) / (r^2/4) = 16 * (k * q1 * q2) / r^2.
Step 4: Comparing the forces
- Comparing the new force F' with the given force phy/4, we have: F' = 16 * (k * q1 * q2) / r^2 = 16 * (phy/4) = 4phy.
Conclusion:
- The force acting between the charges, when the magnitudes are doubled and the distance is halved, is 4phy.
- Therefore, the correct option is (b) 4phy.