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An electric current passes through a long straight wire. At a distance 5 cm from the wire, the magnetic field is B. The field at 20 cm from the wire would be
The correct answer is: B/4
A magnetic field of exerts a force on a particle having a charge 10^{−9}C and moving in te x−y plane. Find the velocity of the particle.
Given
q = 10^{–9} C
Magnetic force
Let velocity of the particle in xy plane be,
Then from the relation
F_{m} = q(V × B)
We have
Comparing the coefficient of we have,
4 × 10^{–10} = 4V_{y} × 10^{–12}
V_{y} = 10^{2} m/s = 100 m/s
and 3.0 × 10^{–10} = –4V_{x} × 10^{–12}
V_{x} = –75 m/s
The correct answer is:
If a charge particle is describing a circle of radius r in a magnetic field with a time period T. Then :
So, T is independent of r.
The correct answer is:
Two wires of same length are shaped into a square and a circle. If they carry same current, ratio of the magnetic moment is
Let length of each wire is L
For square length of each side L/4
A positively charged particle falling freely under gravity enter a region having a uniform horizontal magnetic field pointing north to south the particle will be deflected towards
Given that , V is pointing downwards and B is towards North
As magnetic force in given by,
fm=q(V×B)
Using right hand thumb for negative charge we het the F is towards west
A charged particle enters a magnetic field H with its initial velocity making an angle of 45° with H the path of the particle will be :
The correct answer is: a helix
A wire carrying current i and other carrying current 2i in the same direction produce a magnetic field B at the midpoint. What will be the field when 2i current is switched off?
Magnetic field
B_{2} = 2B_{1}
2B_{1} – B_{1} = B
B_{1} = B
A long metallic cylinder of radius R has a current i flowing through it. The magnetic induction B will vary with distance from the curve as shown in figure.
The correct answer is:
A proton and a deutron both having the same kinetic energy, enter perpendicularly into a uniform magnetic field B. For motion of proton and deutron on circular path of radius R_{p} and R_{d} respectively, the correct statement is :
For charged particle on circular path
For deutron
The correct answer is:
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