Tag: potential difference

Questions Related to potential difference

Electric current is due to drift of electrons in

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

  1. Metallic conductors

  2. Semiconductors

  3. Both (a) and (b) above

  4. None of the above

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Correct Option: A
Explanation:

Answer is A.
When an electric field is applied across the metallic conductors the randomly moving electrons are subjected to electrical forces along the direction of the field. Due to this field, the electrons do not give up their randomness of motion, but they will be shifting towards higher potential. That means the electrons will drift towards higher potential along with their random motions. 
In semiconductors, in addition to electrons, the travelling vacancies in the valence-band electron population (called 'holes'), act as mobile positive charges and are treated as charge carriers. Electrons and holes are the charge carriers in semiconductors.
Hence, electric current is due to drift of electrons in metallic conductors.

In a series circuit.

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

  1. Current flow is same in all the resistors of the circuit.

  2. Potential difference across each resistor in the circuit is same.

  3. Both (1) and (2)

  4. None of these

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Correct Option: A
Explanation:

In series connection same current will flow through each one of them.

State whether given statement is True or False
Conventional current always flows from a body having high electron density to body having to body having low electron density.

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: B
Explanation:

Conventional Current assumes that current flows out of the positive terminal, through the circuit and into the negative terminal of the source. This was the convention chosen during the discovery of electricity.
Not from high electron density to low electron density.

In case of electronic current the charge flows from negatively charged body to the positively charged body. The body which is at higher potential is 

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

  1. negatively charged body

  2. positively charged body

  3. both are at same potential

  4. none of these

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Correct Option: B
Explanation:

By convention a positively charged body is always at a higher potential as compared to negatively charged body . If positive charges like protons or positive ions are free to move they would move from higher potential point to lower potential point.

In case of electronic current the charge flows from negatively charged body to the positively charged body. The body which is at higher potential is positively charged body

Three resistors each of $10 \Omega$ are connected in series to a battery of potential difference 150 v. The current flowing through it is ..... A.

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

  1. 45

  2. 5

  3. 15

  4. 20

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Correct Option: B
Explanation:

Current through a resistance (R) is given by, $V=i*R _{eq}$
$i=150/30$
$i=5$ ampere

A big hallow metal sphere $A$ is charged to $100$ volts and another smaller hollow sphere $B$ is charged to $50$ volts. If B is put inside $A$ and joined with a metallic wire, then the direction of charge flow:-

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

  1. is from $A$ to $B$

  2. is from $B$ to $A$

  3. to charge flows

  4. depends on the radii of spheres

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Correct Option: A

A DC current flows through a vertical wire in the downward direction. For an observer looking at the wire, the direction of magnetic field at a point between him and the wire is:

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

  1. Upward

  2. To the right

  3. To the left

  4. Downward

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Correct Option: B

An aluminium (Al) rod with area of cross-section $4\times 10^{-6}m^2$ has a current of 5A. Flowing through it. Find the drift velocity of electron in the rod. Density of $Al=2.7\times 10^3kgm^{-3}$ and atomic wt.=27. Assume that each Al atom provides one electron.

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

  1. $8.6\times 10^{-4}ms^{-1}$

  2. $6.2\times 10^{-4}ms^{-1}$

  3. $1.2\times 10^{-4}ms^{-1}$

  4. $3.8\times 10^{-3}ms^{-1}$

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Correct Option: C

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