PHY101 Short Notes Set 3

PHY101 Short Notes (VUAnswer

An Introduction to Physics (Virtual University of Pakistan)

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An Introduction to Physics (Virtual University of Pakistan)

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Studocu is not sponsored or endorsed by any college or university

PHY101 Short notes

Q1. Define charge density

When the charges are continuously over a region-a line, the surface of a material, or inside a sphere-we must specify the charge density. Depending upon how many dimensions the region has, we define: (a) For linear charge distribution: dq ds ü (b) For surface charge distribution: dq dA ó (c) For volume charge distribution: dq dv ò The dimensions of are determined from the above definitions.

Q2. Define Gauss’s Law?

Answer: The total electric flux leaving a closed surface is equal to the charge enclosed by the surface divided by  .We can expressed in mathematics form

enclosed q E d A

Q3. Define electric potential?

Answer: The electric potential is the energy of a unit charge in an electric field. So in our MKS units the unit of potential is 1Joule/Coulombs=1Volt. Another useful unit is 1Electron Volt.

Q4. Define 1Ev?

Answer: One electron-volt=enrgy gained by moving one electron charges through one volt. = ø ù 1.6 10 1.6 10 x C x V x J It is useful to note that Kev eV Mev eV Gev eV

Q5. Given a system of charges, we can always compute the force - and hence the potential - That arises from them. Here are some important general statements:

1. Potentials are more positive in regions which have more positive charge.
2. The electric potential is a scalar quantity (a scalar field, actually).
3. The electric potential determines the force through F=− du/dr, and hence the electric

Field because F= qE. d) The electric potential exists only because the electrostatic force is conservative

Q6. Define Capacitor?

Answer: Two conductors isolated from one another and from their surroundings, from a capacitor. These conductors may be of any shape and shape, and at any distance from each other. If a potential difference is created between the conductors (say, by connecting the terminals of a battery to them), then there is an electric field in the space between them. The electric field comes from