JEE Main 2021 (Online) 31st August Morning Shift | Magnetic Effect of Current Question 87 | Physics

JEE Main 2021 (Online) 31st August Morning Shift

MCQ (Single Correct Answer)

-1

A coil having N turns is wound tightly in the form of a spiral with inner and outer radii 'a' and 'b' respectively. Find the magnetic field at centre, when a current I passes through coil:

$${{{\mu _0}IN} \over {2(b - a)}}{\log _e}\left( {{b \over a}} \right)$$

$${{{\mu _0}I} \over 8}\left[ {{{a + b} \over {a - b}}} \right]$$

$${{{\mu _0}I} \over {4(a - b)}}\left[ {{1 \over a} - {1 \over b}} \right]$$

$${{{\mu _0}I} \over 8}\left( {{{a - b} \over {a + b}}} \right)$$

JEE Main 2021 (Online) 27th August Evening Shift

MCQ (Single Correct Answer)

-1

A coaxial cable consists of an inner wire of radius 'a' surrounded by an outer shell of inner and outer radii 'b' and 'c' respectively. The inner wire carries an electric current i₀, which is distributed uniformly across cross-sectional area. The outer shell carries an equal current in opposite direction and distributed uniformly. What will be the ratio of the magnetic field at a distance x from the axis when (i) x < a and (ii) a < x < b ?

$${{{x^2}} \over {{a^2}}}$$

$${{{a^2}} \over {{x^2}}}$$

$${{{x^2}} \over {{b^2} - {a^2}}}$$

$${{{b^2} - {a^2}} \over {{x^2}}}$$

JEE Main 2021 (Online) 27th August Morning Shift

MCQ (Single Correct Answer)

-1

Two ions of masses 4 amu and 16 amu have charges +2e and +3e respectively. These ions pass through the region of constant perpendicular magnetic field. The kinetic energy of both ions is same. Then :

lighter ion will be deflected less than heavier ion

lighter ion will be deflected more than heavier ion

both ions will be deflected equally

no ion will be deflected

JEE Main 2021 (Online) 26th August Morning Shift

MCQ (Single Correct Answer)

-1

The fractional change in the magnetic field intensity at a distance 'r' from centre on the axis of current carrying coil of radius 'a' to the magnetic field intensity at the centre of the same coil is : (Take r < a)

$${3 \over 2}{{{a^2}} \over {{r^2}}}$$

$${2 \over 3}{{{a^2}} \over {{r^2}}}$$

$${2 \over 3}{{{r^2}} \over {{a^2}}}$$

$${3 \over 2}{{{r^2}} \over {{a^2}}}$$

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