A rectangular loop of wire, supporting a mass $m$, hangs with one end in a uniform magnetic field $\vec B$ pointing into the plane of the paper. $A$ clockwise current is set up such that $i> mg/Ba,$ where $a$ is the width of the loop. Then
The weight decends due to a vertical force caused by the magnetic field
The weight moves towards rightward
The weight rises due to a vertical force caused by the magnetic field
None of these
An arbitrary shaped closed coil is made of a wire of length $L$ and a current $I$ ampere is flowing in it. If the plane of the coil is perpendicular to magnetic field $\mathop B\limits^ \to $, the force on the coil is
Three straight parallel current carrying conductors are shown in the figure. The force experienced by the middle conductor of length $25\,cm$ is
Two very long, straight and parallel wires carry steady currents $I$ and $I$ respectively. The distance between the wires is $d$. At a certain instant of time, a point charge $q$ is at a point equidistant from the two wires in the plane of the wires. Its instantaneous velocity $v$ is perpendicular to this plane. The magnitude of the force due to the magnetic field acting on the charge at this instant is
Three long straight wires are connected parallel to each other across a battery of negligible internal resistance. The ratio of their resistances are $3 : 4 : 5$. What is the ratio of distances of middle wire from the others if the net force experienced by it is zero
One of the two small circular coils, (none of them having any self- inductance) is suspended with a $V-$ shaped copper wire, with plane horizontal. The other coil is placed just below the first one with plane horizontal. Both the coils are connected in series with a $dc$ supply. The coils are found to attract each other with a force. Which one of the following statements is incorrect ?