Question Details

Find force on charge q = 1 μC due to unfirmly charged rod as shown in the figure

Options

A

7.5 N

B

6 N

C

12 N

D

18 N

Show Answer

Correct Answer :

Option A

7.5 N

7.5 N

Solution :

From the given figure:
- The total charge on the rod is Q=2 μC=2×10-6 C.
- The length of the rod is L=10 cm=0.1 m.
- The point charge is q=1 μC=1×10-6 C.
- The distance of the point charge q from the nearer end of the rod is a=2 cm=0.02 m.

To find the electrostatic force on the charge q due to the uniformly charged rod, we consider a small element of length dx on the rod at a distance x from the charge q.
The linear charge density of the rod is:
λ=QL

The charge on the small element dx is:
dq=λdx=QLdx

According to Coulomb's Law, the force dF on charge q due to this element dq is:
dF=k·q·dqx2=k·q·QL·x2dx

To find the total force, we integrate this expression over the entire length of the rod, from x=a to x=a+L:
F=aa+Lk·q·QL·x2dx

F=k·q·QL-1xaa+L

F=k·q·QL1a-1a+L

F=k·q·QLLa(a+L)

F=k·q·Qa(a+L)

Now, substitute the given values:
- k=9×109 N·m2/C2
- q=1×10-6 C
- Q=2×10-6 C
- a=0.02 m
- a+L=0.02 m+0.1 m=0.12 m

Substitute these values into the force equation:
F=(9×109)·(1×10-6)·(2×10-6)0.02·0.12

F=18×10-30.0024

F=0.0180.0024=7.5 N

Thus, the electrostatic force on the charge q is 7.5 N.

Unlock Our Free Library

Access expert-curated educational resources and study materials—completely free.

Discover more resources

You may also like

Mock Tests

View All
  • JEE
  • intermediate
  • 3 hours
  • chemistry, mathematics, physics
  • Proctored

  • JEE
  • intermediate
  • 3 hours
  • chemical engineering, mathematics, physics

Ask AI Tutor
5 left
Q1 View Question & Options
AI Tutor is solving this question...
Reading question context & options...