Electrostatic Potential and Capacitance — Physics STD 12 Science — Question

A 4μF conductor is charged to 400 volts and then its plates are joined through a resistance of 1kΩ. The heat produced in the resistance is(a) 0.16 J(b) 1.28 J(c) 0.64 J (d) 0.32 J

How is the electric field at the surface of a charged conductor related to the surface charge density?

An inductance and resistance are connected in series with an A.C circuit. In this circuit.

A magnifying glass is to be used at the fixed object distance of 1 inch. If it is to produce on erect image 5 items magnified, its focal length should be :

Liquids and gases never exhibit:

Electromagnets are made of soft iron because soft iron has:

Range of frequencies allotted for commercial FM radio broadcast is (a) 88 to 108 MHz(b) 88 to 108 kHz(c) 8 to 88 MHz(d) 88 to 108 GHz

As the electron in Bohr orbit of Hydrogen atom passes from state n = 2 to n = 1, the kinetic energy K and potential energy U change as(a) K two-fold, U four-fold(b) K four-fold, U two-fold(c) K four-fold, U also four-fold  (d) K two-fold, U also two-fold

Two electrons in an atom are moving in orbit of radii R and 9R respectively. The ratio of their frequencies will be: