Motional Emf

A jet plane is travelling towards wets at a speed of $1800 \mathrm{km} {\mathrm{h}}^{-1}$. What is the voltage difference developed between the ends of the wing having a span of $25 \mathrm{m}$, if the Earth’s magnetic field at the location has a magnitude of  $5\times {10}^{-4} \mathrm{T}$ and the dip angle is $30°$ ?

Figure shows a rectangular conductor $PQRS$ in which the conductor $PQ$ is free to move in a uniform magnetic field $B$ perpendicular to the plane of the paper. The field extends from $x=0$ to $x=b$ and is zero for $x>b$. Assume that only the arm $PQ$ possesses resistance $r$. When the arm $PQ$ is pulled outward from $x=0$ with constant speed $v$, the joules heating loss from $b\le x<2b$ would be:

The figure given below shows an arrangement by which current flows through the bulb (X) connected with coil B, when a.c. is passed through coil A.


(i) Name the phenomenon involved.

(ii) If a copper sheet is inserted in the gap between the coils, explain how the brightness of the bulb would change.

A loop $\mathrm{ABCD}$ is moving with velocity $v$ towards the right. The magnetic field is $2 \mathrm{T}$. Loop is connected to a resistance of $9 \mathrm{\Omega }$. If the steady current of $2 \mathrm{A}$flows in the loop, then the value of $v$, if loop has resistance of $4 \mathrm{\Omega }$, is (Given $\mathrm{AD} = 30 \mathrm{cm}$)

The figure shows a rod of length $l$ with points $A$ and $B$ on it. The rod is moved in a uniform magnetic field $\left(B_0\right)$ in different ways as shown. In which case, the potential difference $\left(V_A-V_B\right)$ between $A$ and $B$ is minimum?

A conducting square frame of side $a$ and a long straight wire carrying current $I$ are located in the same plane as shown in the figure. The frame moves to the right with a constant velocity $v$. The emf induced in the frame will be proportional to:

A metallic rod of length $l$ is tied to a string of length $2I$ and made to rotate with angular speed $\omega$ on a horizontal table with one end of the string fixed. If there is a vertical magnetic field $B$ in the region, the e.m.f. induced across the ends of the rod is:

A semicircular wire of radius $R$ is rotated with constant angular velocity $\omega$ about an axis passing through one end and perpendicular to the plane of the wire. There is a uniform magnetic field of strength $B$. The induced e.m.f. between the ends is:

A rectangular coil has $60$ turns and its length and width is $20$ and $10 \mathrm{cm}$ respectively. The coil rotates at a speed of $1800$ rotation per minute in a uniform magnetic field of $0.5$ $\mathrm{T}$. Then the maximum induced emf will be-

An athelete runs at a velocity of $30 \mathrm{km}/\mathrm{hr}$, towards east with a $3 meter$ rod. The horizontal component of the earth is $4\times {10}^{-5} weber/m^2$ . If he runs, keeping the rod (i) horizontal and (ii) vertical, the p.d. at the ends of the rod in both the cases, will be-

A straight conductor of length $0.4 \mathrm{m}$ is moved in a magnetic field of $0.9 weber/m^2$ with a velocity of $7\mathrm{m}/\mathrm{s}$. The maximum emf induced in the conductor will be -

An aeroplane having a distance of $50 \mathrm{m}$ between the edges of its wings is flying horizontally with a speed of $720 \mathrm{km}/\mathrm{hour}$ . If the vertical component of the earth's magnetic field is $2\times {10}^{-4} Wb/m^2$, then the induced emf will be -

A wire of length $2 \mathrm{m}$ is moving with a velocity of $1 \mathrm{m}/\mathrm{s}$ normal to a magnetic field of $0.5 Wb/m^2$. The emf induced in it will be $-$

In figure, wires $P_1{Q}_1$ and $P_2{Q}_2,$ both are moving towards right with speed $5 \mathrm{cm} {\sec }^{-1}$ resistance of each wire is $2 \mathrm{\Omega }$. Then current through resistor is $a\times {10}^{-1} \mathrm{mA}$

A conducting $rodAC$ of length $4l$ and mass $m$ is rotating about point $O$ with angular momentum $J.$ A uniform magnetic field $B$ is directed into the paper. Given, $AO=l$ and $OC=3l.$ Then, $V_A-V_C$ is $\lambda$ times $\frac{BJ}{14M}$. What is the value of $\lambda$?

A rod of length $5 \mathrm{cm}$ is fixed at one end and it is rotating with an angular speed of $5 \mathrm{rad}/\mathrm{s}$. There is a magnetic field of $2 \mathrm{T}$ along the axis of rotation of the field. Find the EMF induced in the rod in millivolts.

When a magnet moves near a conducting coil, a current gets induced in the coil. What is the source of this electrical energy generated in the coil?

A conducting rod $PQ$ of length $1 \mathrm{m}$ is moving with a uniform speed $2 {\mathrm{ms}}^{-1}$ in a uniform magnetic field of $4 \mathrm{T}$ which is directed into the paper. A capacitor of capacity $10 \mathrm{\mu F}$ is connected as shown in the figure. Then the charges on the plates of the capacitor are

A rod of length $1 \mathrm{m}$ is kept inclined at an angle of $60°$ with the uniform magnetic field of $0.5 \mathrm{T}$. If the rod is moved with a velocity $10 \mathrm{m} {\mathrm{s}}^{-1}.$ perpendicular to the field, the induced emf is

A copper rod is moved in a magnetic field. The charge developed across its ends will be proportional to _____.