# Topic: Unit I: Electrostatics (Test 1)

Topic: Unit I: Electrostatics
Q.1
Two identical point charges of magnitude –q are fixed as shown in the figure below. A third charge +q is placed midway between the two charges at the point P. Suppose this charge +q is displaced a small distance from the point P in the directions indicated by the arrows, in which direction(s) will +q be stable with respect to the displacement? A. A1 and A2
B. B1 and B2
C. both directions
D. No stable
Explaination / Solution:

Hint: Since V=0 along equatorial line
Workspace
Report
Q.2
Which charge configuration produces a uniform electric field?
A. point Charge
B. infinite uniform line charge
C. uniformly charged infinite plane
D. uniformly charged spherical shell
Explaination / Solution:
No Explaination.

Workspace
Report
Q.3
What is the ratio of the charges |q1/q2| for the following electric field line pattern? A. 1/5
B. 25/11
C. 5
D. 11/25
Explaination / Solution: Workspace
Report
Q.4
An electric dipole is placed at an alignment angle of 30º with an electric field of 2 × 105 N C-1. It experiences a torque equal to 8 N m. The charge on the dipole if the dipole length is 1 cm is
A. 4 mC
B. 8 mC
C. 5 mC
D. 7 mC
Explaination / Solution: Workspace
Report
Q.5
Four Gaussian surfaces are given below with charges inside each Gaussian surface. Rank the electric flux through each Gaussian surface in increasing order. A. D < C < B < A
B. A < B = C < D
C. C < A = B < D
D. D > C > B > A
Explaination / Solution: Workspace
Report
Q.6
The total electric flux for the following closed surface which is kept inside water A. 80q/ε
B. q/40ε
C. q/80ε
D. q/160ε
Explaination / Solution: Workspace
Report
Q.7
Two identical conducting balls having positive charges q1 and q2 are separated by a center to center distance r. If they are made to touch each other and then separated to the same distance, the force between them will be
A. less than before
B. same as before
C. more than before
D. zero
Explaination / Solution: Workspace
Report
Q.8
Rank the electrostatic potential energies for the given system of charges in increasing order. A. 1 = 4 < 2 < 3
B. 2 = 4 < 3 < 1
C. 2 = 3 < 1 < 4
D. 3 < 1 < 2 < 4
Explaination / Solution: Workspace
Report
Q.9
An electric field exists in a certain region of space. Then the potential difference V = Vo – VA, where Vo is the potential at the origin and VA is the potential at x = 2 m is:
A. 10 J
B. – 20 J
C. +20 J
D. -10J
Explaination / Solution: Workspace
Report
Q.10
A thin conducting spherical shell of radius R has a charge Q which is uniformly distributed on its surface. The correct plot for electrostatic potential due to this spherical shell is
A. B. C. D. 