Four particles each having charge q are placed at the vertices of a square of side a. The value of the electric potential at the midpoint of one of the side will be
1. 0
2.
3.
4.
If E be the electric field inside a parallel plate capacitor due to Q and -Q charges on the two plates, then electrostatic force on plate having charge -Q due to the plate having charge +Q will be
(1) -QE
(2)
(3) QE
(4)
A metallic sphere of capacitance , charged to electric potential is connected by a metal wire to another metallic sphere of capacitance charged to electric potential . The amount of heat produced in connecting the wire during the process is:
1.
2.
3.
4. zero
The electric potential at the surface of a charged solid sphere of insulator is 20V. The value of electric potential at its centre will be
1. 30V
2. 20V
3. 40V
4. Zero
The capacitance of a parallel plate capacitor is C. If a dielectric slab of thickness equal to one-fourth of the plate separation and dielectric constant K is inserted between the plates, then new capacitance become
1.
2.
3.
4.
The electric potential at a point at distance 'r' from a short dipole is proportional to
(1)
(2)
(3)
(4)
A hollow charged metal spherical shell has radius R. If the potential difference between its surface and a point at a distance 3R from the center is V, then the value of electric field intensity at a point at distance 4R from the center is
1.
2.
3.
4.
Capacitors are connected in series across a source of emf 20KV. The potential difference across will be
(1) 5 KV
(2) 15 KV
(3) 10 KV
(4) 20 KV
The equivalent capacitance between A and B is as the given figure:
(1)
(2)
(3)
(4) None of these