Tag: magnetic effect of electric current

Questions Related to magnetic effect of electric current

An electron is travelling along the x-direction. It encounters a magnetic field in the ydirection. Its subsequent motion will be

physics magnetic effect of electric current fleming's left hand rule magnetic force magnetic force on a moving charge and current carrying wire

  1. straight line along the x-direction

  2. a circle in the zx-plane

  3. a circle in the yz-plane

  4. a circle in the xy-plane

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Correct Option: B
Explanation:

The magnetic force acting on a charged particle is given by 

$\vec{F}=q(\vec{v}\times \vec{B})$
Hence direction of force acting one electron is $\hat{i}\times \hat{j}=\hat{k}$
The force experienced is in z-direction. So the particle moves in the zx plane.

An electric current runs counterclockwise in a rectangular loop around the outside edge of the page which lies flat on your table. A uniform magnetic field is then turned on directed parallel to the page from the top to bottom. The magnetic force on the page will cause:

physics magnetic effect of electric current fleming's left hand rule magnetic force magnetic force on a moving charge and current carrying wire

  1. the left edge to lift up

  2. the right edge to lift up

  3. the top edge to lift up

  4. the bottom edge to lift up

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Correct Option: C
Explanation:

Current is flowing anticlockwise in the rectangular loop and in the upper edge of page current is flowing towards left and magnetic field is from top to bottom , so by applying Fleming's left hand rule the direction of force is found to be in the upward direction, lifting the top edge up.

A positive charge is at rest in a uniform magnetic field directed to the right. What force does the positive charge feel, due to the magnetic field?

physics magnetic effect of electric current fleming's left hand rule magnetic force magnetic force on a moving charge and current carrying wire

  1. An upward force.

  2. A downward force.

  3. A force to the left.

  4. No force is felt.

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Correct Option: D
Explanation:
For experiencing a magnetic force on a charge  particle, the particle should move in the magnetic field with some velocity. As the velocity of the particle is zero so, the force on the particle is also zero.

The direction of force on a current carrying conductor placed in a magnetic field is given by :

physics magnetic effect of electric current fleming's left hand rule magnetic force magnetic force on a moving charge and current carrying wire

  1. Fleming's Left Hand Rule

  2. Fleming's Right Hand Rule

  3. End Rule

  4. Right Hand Palm Rule

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Correct Option: A
Explanation:

The direction of this force is always right angles to the plane containing both the conductor and the magnetic field, and is predicted by Fleming’s Left-Hand Rule.

A vertical wire carries a current in upward direction. An electron beam sent horizontally towards the wire will be deflected (gravity free space) :

physics magnetic effect of electric current fleming's left hand rule magnetic force magnetic force on a moving charge and current carrying wire

  1. towards right

  2. towards left

  3. upwards

  4. downwards

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Correct Option: C
Explanation:

$F= q(\vec{v} \times \vec{B})= (-e)( -v\hat{i}\times (-B\hat{k}))=evB\hat{j}$
Thus, force on the electron beam is along the +ve y-axis.

How will be the direction of force will get changed, if the current is reversed in the conductor placed in a magnetic field?

physics magnetic effect of electric current fleming's left hand rule magnetic force magnetic force on a moving charge and current carrying wire

  1. Direction of force rotates by right angle

  2. Direction of force is reversed.

  3. Direction of force remains same

  4. Can't say

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Correct Option: B

A proton is projected horizontally eastward in a uniform magnetic field, which is horizontal and southward in direction. The proton will be deflected

physics magnetic effect of electric current fleming's left hand rule magnetic force magnetic force on a moving charge and current carrying wire

  1. upward

  2. downward

  3. northward

  4. southward

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Correct Option: B
Explanation:

By Fleming's left hand rule, taking velocity (middle finger) in east direction and magnetic field (index finger) in south direction, we get force (thumb) in vertically downward direction.

An electron enters a magnetic field at right angles to it. The direction of force acting on the electron will be

physics magnetic effect of electric current fleming's left hand rule magnetic force magnetic force on a moving charge and current carrying wire

  1. to the right.

  2. to the left.

  3. out of the page.

  4. into the page.

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Correct Option: D

Which rule determines the direction of force experienced by a current Carrying straight conductor placed in a magnetic field which is perpendicular to it.

physics magnetic effect of electric current fleming's left hand rule magnetic force magnetic force on a moving charge and current carrying wire

  1. Maxwell right hand grip rule

  2. Fleming's left hand rule

  3. Fleming's right hand rule

  4. None

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Correct Option: B
Explanation:

We considered the direction of the current and that of the magnetic field perpendicular to each other and found that the force is perpendicular to both of them. The three directions can be illustrated through a simple rule, called Flemings left-hand rule. According to this rule, stretch the thumb, forefinger and middle finger of your left hand such that they are mutually perpendicular. If the first finger points in the direction of magnetic field and the second finger in the direction of the current, then the thumb will point in the direction of motion or the force acting on the conductor.

In the statement of Fleming's left hand rule, magnetic field is represented by

physics magnetic effect of electric current fleming's left hand rule magnetic force magnetic force on a moving charge and current carrying wire

  1. thumb

  2. fore finger

  3. middle finger

  4. none

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Correct Option: B
Explanation:

The direction of the current and that of the magnetic field perpendicular to each other and found that the force is perpendicular to both of them. The three directions can be illustrated through a simple rule, called Flemings left-hand rule. According to this rule, stretch the thumb, forefinger and middle finger of your left hand such that they are mutually perpendicular. If the first finger points in the direction of magnetic field and the second finger in the direction of the current, then the thumb will point in the direction of motion or the force acting on the conductor.