Advertisements
Advertisements
प्रश्न
A long straight horizontal cable carries a current of 2.5 A in the direction 10° south of west to 10° north of east. The magnetic meridian of the place happens to be 10° west of the geographic meridian. The earth’s magnetic field at the location is 0.33 G, and the angle of dip is zero. Locate the line of neutral points (ignore the thickness of the cable)? (At neutral points, magnetic field due to a current-carrying cable is equal and opposite to the horizontal component of earth’s magnetic field.)
Advertisements
उत्तर
Current in the wire, I = 2.5 A
Angle of dip at the given location on earth, δ = 0°
Earth’s magnetic field, H = 0.33 G = 0.33 × 10−4 T
The horizontal component of the earth’s magnetic field is given as:
HH = H cos δ
= 0.33 × 10−4 × cos 0°
= 0.33 × 10−4 T
The magnetic field at the neutral point at a distance R from the cable is given by the relation:
HH = `(μ_0"I")/(2π"R")`
Where,
μ0 = Permeability of free space = 4π × 10−7 T mA−1
∴ R = `(μ_0"I")/(2π"H"_"H")`
= `(4π xx 10^-7 xx 2.5)/(2π xx 0.33 xx 10^-4)`
= 15.15 × 10−3 m
= 1.51 m
Hence, a set of neutral points parallel to and above the cable are located at a normal distance of 1.51 cm.
संबंधित प्रश्न
A conducting rod held horizontally along East- West direction is dropped from rest from a certain height near the Earth’s surface. Why should there be an induced emf across the end of the rod? Draw a plot showing the instantaneous variation of emf as a function of time from the instant it begins to fall.
A compass needle which is allowed to move in a horizontal plane is taken to a geomagnetic pole. It ______.
What is the angle of dip at a place where the horizontal component `(B_H)` and vertical component `(B_V)` of earth’s magnetic field are equal :
State Tangent Law in magnetism.
Choose the correct option.
The horizontal and vertical component of magnetic field of Earth are same at someplace on the surface of Earth. The magnetic dip angle at this place will be
Choose the correct option.
A place where the horizontal component of Earth's magnetic field is zero lies at
Answer the following question in detail.
How does the magnetic declination vary with latitude? Where is it minimum?
Answer the following question in detail.
Define the Angle of Dip.
The charged currents in the outer conducting regions of the earth’s core are thought to be responsible for earth’s magnetism. What might be the ‘battery’ (i.e., the source of energy) to sustain these currents?
At a certain location in Africa, a compass points 12° west of the geographic north. The north tip of the magnetic needle of a dip circle placed in the plane of magnetic meridian points 60° above the horizontal. The horizontal component of the earth’s field is measured to be 0.16 G. Specify the direction and magnitude of the earth’s field at the location.
A long straight horizontal cable carries a current of 2.5 A in the direction 10° south of west to 10° north of east. The magnetic meridian of the place happens to be 10° west of the geographic meridian. The earth’s magnetic field at the location is 0.33 Gauss, and the angle of dip is zero. Locate the line of neutral points. (Ignore the thickness of the cable).
If the change in value of g at height h above the surface of the earth is the same as at a depth d below the surface of the earth, when both d and h are much smaller than the radius of the Earth, then which one of the following is true?
Assume the dipole model for earth’s magnetic field B which is given by BV = vertical component of magnetic field = `mu_0/(4pi) (2m cos theta)/r^3` BH = Horizontal component of magnetic field = `mu_0/(4pi) (sin theta m)/r^3` θ = 90° – lattitude as measured from magnetic equator. Find loci of points for which (i) |B| is minimum; (ii) dip angle is zero and (iii) dip angle is ± 45°.
Consider the plane S formed by the dipole axis and the axis of earth. Let P be point on the magnetic equator and in S. Let Q be the point of intersection of the geographical and magnetic equators. Obtain the declination and dip angles at P and Q.
The earth's magnetic field lines resemble that of a dipole at the centre of the earth. If the magnetic moment of this dipole is close to 8 × 1022 Am2, the value of earth's magnetic field near the equator is close to ______. (radius of the earth = 6.4 × 106 m)
