A wire carrying $I$ is shaped as shown. Section $AB$ is a quarter circle of radius $r.$ The magnetic field at $C$ is directed
along the bisector of the angle $ACB$, away from $AB$
along the bisector of the angle $ACB$, towards $AB$
perpendicular to the plane of the paper, directed into the paper
at an angle $\pi /4$ to the plane of the paper
A thin wire of length $l$ is carrying a constant current. The wire is bent to form a circular coil. If radius of the coil, thus formed, is equal to $R$ and number of turns in it is equal to $n$, then which of the following graphs represent $(s)$ variation of magnetic field induction $(b)$ at centre of the coil
The magnetic field at the centre of a circular current carrying-conductor of radius $r$ is $B_c$. The magnetic field on its axis at a distance $r$ from the centre is $B_a$. The value of $B_c : B_a$ will be :-
A beam of neutrons performs circular motion of radius, $r=1 \,m$. Under the influence of an inhomogeneous magnetic field with inhomogeneity extending over $\Delta r=0.01 \,m$. The speed of the neutrons is $54 \,m / s$. The mass and magnetic moment of the neutrons respectively are $1.67 \times 10^{-27} \,kg$ and $9.67 \times 10^{-27} \,J / T$. The average variation of the magnetic field over $\Delta r$ is approximately ....... $T$
A vertical straight conductor carries a current vertically upwards. A point $P$ lies to the east of it at a small distance and another point $Q$ lies to the west at the same distance. The magnetic field at $P$ is
A coil having $N$ turns is wound tightly in the form of a spiral with inner and outer radii $a$ and $b$ respectively. When a current $i$ passes through the coil, the magnetic field at the centre is