Electric Charges and Fields

The angle of dip at the poles and the equator respectively are

• 30^o, 60^o

• 0^o, 90^o

• 45^o, 90^o

• 90^o, 0^o

Assertion:  The conductivity of an electrolyte is very low as compared to a metal at room temperature. 

Reason:  The number density of free ions in electrolyte is much smaller as compared to the number density of free electrons in metals. Further, ions drift much more slowly, being heavier.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

A particle of charge q and mass m starts moving from the origin under the action of an electric field $\overrightarrow{\mathrm{E}}$ = E₀$\hat{\mathrm{i}}$  and $\overrightarrow{\mathrm{B}} = {\mathrm{B}}_0 \hat{\mathrm{i}}$ velocity  $\overrightarrow{\mathrm{v}} = {\mathrm{v}}_0\widehat{ \mathrm{j}}$. The speed of the particle will become $\frac{\sqrt{5}}{2} {\mathrm{\nu }}_0$ after a time

• $\frac{\mathrm{m} {\mathrm{\nu }}_0}{\mathrm{q} {\mathrm{E}}_0}$

• $\frac{\mathrm{m} {\mathrm{\nu }}_0}{2\mathrm{q} {\mathrm{E}}_0}$

• $\frac{\sqrt{3} {\mathrm{m\nu }}_0}{2\mathrm{q} {\mathrm{E}}_0}$

• $\frac{\sqrt{5} {\mathrm{m\nu }}_0}{2\mathrm{q} {\mathrm{E}}_0}$

Assertion:  Magnetic lines forms closed loops in nature. 

Reason: Mono-magnetic pole does not exist in nature.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

An electron projected with velocity $\overrightarrow{\mathrm{v}} = {\mathrm{v}}_0 \hat{\mathrm{i}}$ in the electric field $\overrightarrow{\mathrm{E}} = {\mathrm{E}}_0 \hat{\mathrm{j}}$. Trace the path followed by the electron E₀.

• Parabola

• Circle

• Straight line in + y direction.

• Straight line in -y direction

Assertion:  Magnetic force is always perpendicular to the magnetic field.

Reason:  Electric force is along the direction of electric field.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion: A charged particle can be accelerated in a cyclotron by the alternate distribution of the field.

Reason: Energy of the charged particle is increased by the field applied. 

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion:  At rest, radium is decayed into Radon and an $\mathrm{\alpha }$-particle. They both moves back to back of each other. 

Reason: Splitting of radioactive particle is based on conservation of linear momentum.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion: Gauss's law shows diversion when inverse square law is not obeyed.

Reason: Gauss's law is a consequence of conservation of charges.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion:  Gauss's law can't be used to calculate electric field near electric an electric dipole.

Reason: Electric dipole don't have symmetrical charge distribution.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not correct explaination of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.