a circular loop of radius r carrying current i lies in x y

A circular loop of radius $$R,$$ carrying current $$I,$$ lies in $$x - y$$ plane with its centre at origin. The total magnetic flux through $$x - y$$ plane is

A. directly proportional to $$I$$

B. directly proportional to $$R$$

C. inversely proportional to $$R$$

D. zero

Answer : zero

Solution :
The magnetic lines of force created due to current will be in such a way that on $$x - y$$ plane these lines will be perpendicular. Further, these lines will be in circular loops. The number of lines moving downwards in $$x - y$$ plane will be same in number to that coming upwards of the $$x - y$$ plane. Therefore, the net flux will be zero. One such magnetic line is shown in the figure.
Magnetic Effect of Current mcq solution image

Magnetic Effect of Current mcq solution image

Releted MCQ Question on
Electrostatics and Magnetism >> Magnetic Effect of Current

Releted Question 1

A conducting circular loop of radius $$r$$ carries a constant current $$i.$$ It is placed in a uniform magnetic field $${{\vec B}_0}$$ such that $${{\vec B}_0}$$ is perpendicular to the plane of the loop. The magnetic force acting on the loop is

A. $$ir\,{B_0}$$

B. $$2\pi \,ir\,{B_0}$$

C. zero

D. $$\pi \,ir\,{B_0}$$

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Releted Question 2

A battery is connected between two points $$A$$ and $$B$$ on the circumference of a uniform conducting ring of radius $$r$$ and resistance $$R.$$ One of the arcs $$AB$$ of the ring subtends an angle $$\theta $$ at the centre. The value of the magnetic induction at the centre due to the current in the ring is

A. proportional to $$2\left( {{{180}^ \circ } - \theta } \right)$$

B. inversely proportional to $$r$$

C. zero, only if $$\theta = {180^ \circ }$$

D. zero for all values of $$\theta $$

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Releted Question 3

A proton, a deuteron and an $$\alpha - $$ particle having the same kinetic energy are moving in circular trajectories in a constant magnetic field. If $${r_p},{r_d},$$ and $${r_\alpha }$$ denote respectively the radii of the trajectories of these particles, then

A. $${r_\alpha } = {r_p} < {r_d}$$

B. $${r_\alpha } > {r_d} > {r_p}$$

C. $${r_\alpha } = {r_d} > {r_p}$$

D. $${r_p} = {r_d} = {r_\alpha }$$

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Releted Question 4