Two metallic rings of radius $R$ are rolling on a metallic rod. $A$ magnetic field of magnitude $B$ is applied in the region. The magnitude of the potential difference between point $A$ and point $C$ on the two rings (as shown) will be:

$A$ rod of length $l$ is oscillating as a physical pendulum about one of its ends with a small angular amplitude $\alpha$ in a crossed magnetic field $B$. The maximum $emf$ induced in the rod will be:

$A$ jet plane is travelling towards the west at a speed of $1800\, km/h$. What is the voltage difference developed between the ends of the wing having a span of $25\, m$,if the Earth's magnetic field at the location has a magnitude of $5 \times 10^{-4}\, T$ and the dip angle is $30^{\circ}$?

Two identical conductors $P$ and $Q$ are placed on two frictionless rails $R$ and $S$ in a uniform magnetic field directed into the plane. If $P$ is moved in the direction shown in the figure with a constant speed,then rod $Q$

An aircraft with a wingspan of $40 \text{ m}$ flies with a speed of $1080 \text{ km h}^{-1}$ in the eastward direction at a constant altitude in the northern hemisphere,where the vertical component of the earth's magnetic field is $1.75 \times 10^{-5} \text{ T}$. The emf developed between the tips of the wings is: (in $\text{ V}$)

$A$ square-shaped conducting wire loop of dimension $a$ moving parallel to the $X$-axis approaches a square region of size $b$ $(a < b)$,where a uniform magnetic field $B$ exists pointing into the plane of the paper (see figure). As the loop passes through this region,the plot correctly depicting its speed $v$ as a function of $x$ is