The energy stored in a sphere of 10cm radius when the sphere is charged to a potential of 300 volt is

The potential energy of a proton is 3.2x10^-18J at a particular point. The electric potential at this point is

Capacitance of a capacitor becomes 7/6 times its original value if a dielectric slab of thickness,t=2/3d is introduced in between the plates.d is the separation between the plates.The dielectric constant of the di-electric slab is

Two wires A and B,made of same material and having their lengths in the ratio 6:1 are connected in series.The potential differences across the wires are 3V and 2V respectively.If r_A and r_B the radii of A and B respectively,then r_A/r_B is

When a dielectric slab of the same area of cross-section and thickness equal to 2/3 of the separation is introduced between the plates of a parallel plate capacitor, its capacitance becomes 2.25 times the original value. The dielectric constant of the material of the slab is

A charge of 10 units is divided so that force between the two charges is maximum when placed 2cm apart. The two charges are

A condenser of 20μF is charged to a certain voltage and then discharged through a 4x10⁶Ω resistor.The time taken for the condenser to lose 63% of its charge is

The charge stored in a capacitor is 20μC and the potential difference across the plates is 500V,its capacity is

Two spheres of radii 12 cm and 16 cm have equal charge. The ratio tstored in the condenser is

Charges +50,+20,+30 and -100 nano coulomb are placed at the four corners of a square of side 5√2cm.The potential at the intersection point of diagonals is