Chapter Chosen

Electric Charges and Fields

Book Chosen

Physics Part I

Subject Chosen

Physics

Book Store

Download books and chapters from book store.
Currently only available for.
CBSE Gujarat Board Haryana Board

Previous Year Papers

Download the PDF Question Papers Free for off line practice and view the Solutions online.
Currently only available for.
Class 10 Class 12

Electric Charges and Fields

Is the electric force between two electrons greater than the gravitational force between them? If so by what factor?

Electrostatic force =

\frac{K Q_{1} Q_{2}}{r^{2}}

Gravitational force=

\frac{G m_{1} m_{2}}{r^{2}}

On dividing the two we get,

\frac{\frac{{KQ}_{1} Q_{2}}{r^{2}}}{\frac{{Gm}_{1} m_{2}}{r^{2}}}

\Rightarrow

\frac{9.0 \times 10^{9} \times {(1.6 \times 10^{- 19})}^{2}}{6.67 \times 10^{- 11} \times {(9.1 \times 10^{- 31})}^{2}}

\Rightarrow

4 \times 10^{42}

Therefore, Electrostatic force between two electrons is greater than gravitational force by a factor of 10⁴².

1181 Views

How does the force between two point charges change, if the dielectric constant of the medium in which they are kept decreases?

Dielectric constant of a medium is defined as the ratio of forces between two charges placed in vacuum to medium without any change in magnitude of charges and their distance.

∴

K = \frac{F_{0}}{F}

\Rightarrow

F = \frac{F_{0}}{K}

i.e.,

[F \propto \frac{1}{k}]

Therefore, as K decreases there will be an increase in force.

1732 Views

Two electric field lines never cross each other. Why?

Two electric field lines never cross each other. If they intersect, then at the point of intersection two tangents can be drawn indicating two directions of electric field which is never possible.

392 Views

How does a torque affect the dipole in an electric field?

The torque tends to align the dipole in the direction of the electric field.

801 Views

A glass rod rubbed with silk acquires a charge + 1.6 x 10^–12 C. What is the charge on the silk?

Charge on silk is equal and opposite to charge on glass rod
i.e., q = – 1.6 x 10^–12 C.

919 Views