Tag: physics

Questions Related to physics

When you flip a switch to turn on a light, the delay before the light turns on is determined by :

physics electric current, potential difference and resistance electric potential and potential difference potential difference current in electric circuits

  1. The speed of the electric fields moving in the wire.

  2. the drift speed of the electrons in the wire.

  3. the number of electron collisions per second in the wire.

  4. none of these, since the light comes instantly.

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Correct Option: C

A vertical wire carries a current in upward direction. If an electron beam sent horizontally towards the wire, then it will deflected.

physics electric current, potential difference and resistance electric potential and potential difference potential difference current in electric circuits

  1. vertically downwards and perpendicular to the plane of the paper

  2. vertically upwards and perpendicular to the plane of the paper

  3. In the plane of the paper

  4. No deflection

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Correct Option: A

If the strenath of the majestic field produced $10 \mathrm { cm }$ away from a infinitely long straight conductor is $10 ^ { - 5 } \text { weber/m } ^ { 2 }$ the value of the current flowing in the conductor will be:

physics electric current, potential difference and resistance electric potential and potential difference potential difference current in electric circuits

  1. $5\ ampere$

  2. $10\ ampere$

  3. $500\ ampere$

  4. $1000\ ampere$

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Correct Option: A

If current density in a conducting wire is proportional to the distance r from the axis of the conductor, then find magnetic field at the position r<R , where R is the radius of cross section of the conductor.('i'is the current in conducting wire)

physics electric current, potential difference and resistance electric potential and potential difference potential difference current in electric circuits

  1. $ \frac { \mu _0ir^2 }{2 \pi R^3} $

  2. $ \frac { \mu _0ir^2 }{4 \pi R^3} $

  3. $ \frac { \mu _0ir^2 }{2 \pi R^2} $

  4. $ \frac { \mu _0ir^2 }{2 \pi R^4} $

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Correct Option: A

Electric current flows from positive terminal of battery to negative terminal.

physics electric current, potential difference and resistance electric potential and potential difference potential difference current in electric circuits

  1. True

  2. False

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Correct Option: A

Two conducting parallel plates areseparated by a distance of 0.001$\mathrm { m } . \mathrm { A } 9 \mathrm { V }$battery is connected across the plates.Find out the electric field between the plates? 

physics electric current, potential difference and resistance electric potential and potential difference potential difference current in electric circuits

  1. 9000$\mathrm { V } / \mathrm { m }$

  2. 900$\mathrm { Vim }$

  3. 9$\mathrm { V } / \mathrm { m }$

  4. .9$\mathrm { V } / \mathrm { m }$

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Correct Option: A

The number of free electrons passing through the filament of an electric lamp is one hour when the current through the filament is 0.32 A will be 

physics electric current, potential difference and resistance electric potential and potential difference potential difference current in electric circuits

  1. $3\times { 10 }^{ 22 }$

  2. $2\times { 10 }^{ 26 }$

  3. $7.2\times { 10 }^{ 19 }$

  4. $7.2\times { 10 }^{ 21 }$

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Correct Option: D

The current density $ \bar { j }  $ at cross-sectional area $ \bar { A } = (2 \hat {i} + 4 \hat {j} )mm^{-2}$  is $(2 \hat {j} + 2 \hat {k} ) A m^{-2} $ The current following through the cross-sectional area is

physics electric current, potential difference and resistance electric potential and potential difference potential difference current in electric circuits

  1. $ 12 \mu A $

  2. $ 8 \mu A $

  3. $ 4 \mu A $

  4. zero

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Correct Option: B

A flow of $10^{12}$ electrons per minute in a conducting wire constitutes a current of 

physics electric current, potential difference and resistance electric potential and potential difference potential difference current in electric circuits

  1. $1.6 \times 10^{-7}\, A$

  2. $1.6 \times 10^{-8}\, A$

  3. $2.67 \times 10^{-9}\, A$

  4. `$2.67 \times 10^{-10}\, A$

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Correct Option: C

If 1 mole of electrons contains $ 6.02 \times 10^{23} $ electrons, the value of faraday constant, F, in coul/mole is :

physics electric current, potential difference and resistance electric potential and potential difference potential difference current in electric circuits

  1. $ \frac {96320}{2} $

  2. $ 96320 \times 2 $

  3. 96320

  4. $ 6.6 \times 10^{19} $

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Correct Option: A