EASY
JEE Main
IMPORTANT
Earn 100

In the figure (a), wire 1 consists of a circular arc and two radial lengths; it carries current i1=0.20 A in the direction indicated. Wire 2, shown in cross-section, is long, straight, and perpendicular to the plane of the figure. Its distance from the centre of the arc is equal to the radius R of the arc, and it carries a current i2 that can be varied. The two currents set up a net magnetic field B at the centre of the arc. Figure (b) gives the square of the field's magnitude B2 plotted versus the square of the current i22 .The vertical scale is set by Bs2=10.0×10-10 T2.What angle is subtended by the arc? 

(a) Question Image

(b) Question Image

Important Questions on Magnetic Fields Due to Currents

MEDIUM
JEE Main
IMPORTANT

 In the figure, current i=2.2 A is set up in a long hairpin conductor formed by bending a wire into a semicircle of radius R=8.5 mm . Point b is midway between the straight sections and so distant from the semicircle that each straight section can be approximated as being an infinite wire. What are the (a) magnitude and (b) direction (into or out of the page) of B at a and the (c) magnitude and (d) direction of B at b?

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EASY
JEE Main
IMPORTANT

A current is set up in a wire loop consisting of a semicircle of radius 4.50 cm, a smaller concentric semicircle, and two radial straight lengths, all in the same plane. Figure a shows the arrangement but is not drawn to scale. The magnitude of the magnetic field produced at the center of curvature is 47.25 μT . The smaller semicircle is then flipped over (rotated) until the loop is again entirely in the same plane (Fig. b).The magnetic field produced at the (same) center of curvature now has magnitude 15.75 μT, and its direction is reversed from the initial magnetic field. What is the radius of the smaller semicircle? 

(a) Question Image

(b) Question Image

EASY
JEE Main
IMPORTANT

The figure shows two current segments. The lower segment carries a current of i1=0.40 A and includes a semicircular arc with radius 5.0 cm, angle 180°, and center point P. The upper segment carries current i2=3i1 and includes a circular arc with radius 4.0 cm, angle 120°, and the same center point P . What is the (a) magnitude and (b) direction of the net magnetic field B at P for the indicated current directions? What are the (c) magnitude and (d) direction of B if i1 is reversed? 

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MEDIUM
JEE Main
IMPORTANT

The figure (a) shows two wires, each carrying a current. Wire 1 consists of a circular arc of radius R and two radial lengths; it carries current i1=1.5 A in the direction indicated. Wire 2 is long and straight; it carries a current i2 that can be varied; and it is at distance R2 from the centre of the arc. The net magnetic field B due to the two currents is measured at the centre of curvature of the arc. Figure (b) is a plot of the component of B in the direction perpendicular to the figure as a function of current i2. The horizontal scale is set by i2s=1.00 A What is the angle subtended by the arc? 

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HARD
JEE Main
IMPORTANT

In the figure two long straight wires (shown in cross section) carry the currents i1=30.0 mA and i2=50.0 mA directly out of the page. They are equal distances from the origin, where they set up a magnetic field B . To what value must current i1 be changed in order to rotate B by 25° clockwise? 

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MEDIUM
JEE Main
IMPORTANT

In the figure, a wire forms a semicircle of radius R=9.26 cm and two (radial) straight segments each of length L=13.1 cm. The wire carries current i=32.3 mA.What is the (a) magnitude and (b) direction (into or out of the page) of the net magnetic field at the semicircle's center of curvature C ?

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HARD
JEE Main
IMPORTANT

The figure shows a snapshot of a proton moving at velocity v=(-380 m s-1 )j^ towards a long straight wire with current, i=470 mA . At the instant shown, the proton's distance from the wire is d=2.89 cm. In unit-vector notation, what is the magnetic force on the proton due to the current? 

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MEDIUM
JEE Main
IMPORTANT

A straight conductor carrying current i=15 A splits into identical semicircular arcs as shown in the figure. What is the magnetic field at the center C of the resulting circular loop? 

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