Tag: magnetic effects of current and magnetism

Questions Related to magnetic effects of current and magnetism

In a region, steady and uniform electric and magnetic fields are present. These two fields are parallel to other. A charged particle is released from rest in this region. The path of the particle will be a:

properties of magnet magnetic field moving charges and magnetism magnetic effects of current and magnetism physics

  1. circle

  2. helix

  3. straight line

  4. ellipse

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Correct Option: A

The magnetic lines of force like electrical lines of force

properties of magnet magnetic field moving charges and magnetism magnetic effects of current and magnetism physics

  1. Are closed

  2. Are not closed

  3. Are open

  4. Are not open

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Correct Option: D

Assertion: Basic difference between electric lines and magnetic lines of force is that former are discontinuous and the latter are continuous
Reason: No electric lines of forces exit inside charged conductor but magnetic lines do exist inside magnet

properties of magnet magnetic field moving charges and magnetism magnetic effects of current and magnetism physics

  1. Both A and R are true and R is the correct explanation of A

  2. Both A and R are true and R is not correct explanation of A

  3. A is true, but R is false

  4. A is false, but R is true

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Correct Option: A

If a charged particle goes unaccelerated in a region containing electric and magnetic fields:

properties of magnet magnetic field moving charges and magnetism magnetic effects of current and magnetism physics

  1. ${\vec E}$ must be parallel to ${\vec B}$

  2. ${\vec V}$ must be perpendicular to Electric field

  3. ${\vec V}$ must be parallel to ${\vec B}$

  4. $E$ must be equal to $vB$.

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Correct Option: D
Explanation:

velocity must be perpendicular to B and d)E must be equal to vB. Explanation: Lorenz force is computed as F = q (E + v × B)

So, if particle is accelerated we must have qE = qvB and v × B = −vB First is possible when d is true and second is possible when d is true

An AC rms voltage of 2$\mathrm { V }$ having a frequeney of 50$\mathrm { KH }$ is applied to a condenser of capacity of 10 $\mu F$ The maximum value of the magnetic field between the plates of the condenser if the radius of plate is 10$\mathrm { cm }$ is

properties of magnet magnetic field moving charges and magnetism magnetic effects of current and magnetism physics

  1. 0.4$\pi \mu T$

  2. 4$\pi \mu T$

  3. 4$\mu T$

  4. 40$\pi \mu T$

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Correct Option: B

The magnetic fields of atoms in a material are grouped together and aligned to form _________.

properties of magnet magnetic field moving charges and magnetism magnetic effects of current and magnetism physics neutral points magnetic poles and magnetic compass

  1. Strong magnetic fields

  2. An area of magnetic field

  3. A region called magnetic domain

  4. A bar magnet

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Correct Option: C
Explanation:

A magnetic domain is a region within a magnetic material in which the magnetization is in a uniform direction. This means that the individual magnetic moments of the atoms are aligned with one another and they point in the same direction.

The magnetic fields of atoms in a material are grouped together and aligned to form  region called magnetic domain

The smallest magnet available is ___________.

properties of magnet magnetic field moving charges and magnetism magnetic effects of current and magnetism physics neutral points magnetic poles and magnetic compass

  1. a bar magnet with an area of $1 mm^2$

  2. a spinning electron

  3. a magnetic dipole

  4. a molecule or atom with a magnetic dipole

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Correct Option: B
Explanation:

An electron is not a spinning ball of charge and the intrinsic spin of particles cannot be understood in such terms. a value of the ratio between the magnetic moment and the angular momentum that is a factor 2 too small.

The smallest magnet available is a spining electron.

The magnetic domains of an unmagnetised object are found ___________.

properties of magnet magnetic field moving charges and magnetism magnetic effects of current and magnetism physics neutral points magnetic poles and magnetic compass

  1. Parallel to each other

  2. Perpendicular to each other

  3. Pointing towards south

  4. Pointing in different direction

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Correct Option: D
Explanation:

A magnetic domain is the region in which the magnetic fields of atoms are grouped together and aligned. In an unmagnetized object the magnetic domains are pointing at different directions.

The primary origin of magnetism lies in the

properties of magnet magnetic field moving charges and magnetism magnetic effects of current and magnetism physics neutral points magnetic poles and magnetic compass

  1. atomic current and intrinsic spin of electrons.

  2. polar and non polar nature of molecules.

  3. pauli exclusion principle.

  4. electronegative nature of materials

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Correct Option: A
Explanation:

Atomic currents and intrinsic spins of electrons are responsible for origin of magnetism.

If we go inside a mine and drop a $104 lb$  iron ball and $1$ lb aluminum ball from the top of a high platform, neglecting air resistance.

properties of magnet magnetic field moving charges and magnetism magnetic effects of current and magnetism physics neutral points magnetic poles and magnetic compass

  1. Both will reach the floor at the same time

  2. $1$ lb weight will reach the floor first

  3. $10$ lb weight will reach the floor first

  4. It is not possible to indicate which of the two will reach the floor first without further data

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Correct Option: A
Explanation:
In real life the one having less volume and more weight will reach first

but in ideal situation where viscosity of air is neglected both will hit ground at same time irrespective of their masses if dropped from the same height 

this is because the acceleration produced due to gravity does not depend on the body.