02. Motional Electromotive Force (MEF)
Electro Magnetic Induction

154685 The distance between rails is $2 \mathrm{~m}$, which is parallel to earth magnetic meridian. Vertical component of earth magnetic field is $1.25 \times 10^{-4}$ tesla. If the speed of the train is $4 \mathrm{~m} / \mathrm{s}$, then induced emf across the axle is

1 $10^{-4} \mathrm{~V}$
2 $10^{-2} \mathrm{~V}$
3 $10^{-1} \mathrm{~V}$
4 $10^{-3} \mathrm{~V}$
Electro Magnetic Induction

154687 A disc of radius $0.1 \mathrm{~m}$ is rotating with a frequency $10 \mathrm{rev} / \mathrm{s}$ in a normal magnetic field of strength $0.1 \mathrm{~T}$. Net induced emf is

1 $2 \pi \times 10^{-2} \mathrm{~V}$
2 $\pi \times 10^{-2} \mathrm{~V}$
3 $\frac{\pi}{2} \times 10^{-2} \mathrm{~V}$
4 None of these
Electro Magnetic Induction

154689 The loop shown moves with a velocity $v$ in a uniform magnetic field of magnitude $B$, directed into the paper. The potential difference between $P$ and $Q$ is e. Then :

1 $\mathrm{e}=\frac{1}{2} \mathrm{Blv}$
2 $\mathrm{e}=$ Blv
3 $\mathrm{P}$ is negative with respect to $\mathrm{Q}$
4 $Q$ is positive with respect to $P$.
Electro Magnetic Induction

154690 A square loop of wire of side $5 \mathrm{~cm}$ is lying on a horizontal table. An electromagnet, above and to one side of the loop is turned on, causing a uniform magnetic field downward at an angle of $60^{\circ}$ to the vertical as shown in the figure, The magnetic induction is $0.50 \mathrm{~T}$. The average induced emf in the loop, if the field increases from zero to its final value in $0.2 \mathrm{~s}$ is

1 $5.4 \times 10^{-3} \mathrm{~V}$
2 $3.12 \times 10^{-3} \mathrm{~V}$
3 $0.25 \times 10^{-3} \mathrm{~V}$
4 zero
Electro Magnetic Induction

154686 A conducting $\operatorname{rod} \mathrm{AB}$ moves parallel to $\mathrm{X}$-axis in a uniform magnetic field, pointing in the positive z-direction. The end $A$ of the rod gets

1 positively charged
2 negatively charged
3 neutral
4 first positively charged and then negatively charged
Electro Magnetic Induction

154685 The distance between rails is $2 \mathrm{~m}$, which is parallel to earth magnetic meridian. Vertical component of earth magnetic field is $1.25 \times 10^{-4}$ tesla. If the speed of the train is $4 \mathrm{~m} / \mathrm{s}$, then induced emf across the axle is

1 $10^{-4} \mathrm{~V}$
2 $10^{-2} \mathrm{~V}$
3 $10^{-1} \mathrm{~V}$
4 $10^{-3} \mathrm{~V}$
Electro Magnetic Induction

154687 A disc of radius $0.1 \mathrm{~m}$ is rotating with a frequency $10 \mathrm{rev} / \mathrm{s}$ in a normal magnetic field of strength $0.1 \mathrm{~T}$. Net induced emf is

1 $2 \pi \times 10^{-2} \mathrm{~V}$
2 $\pi \times 10^{-2} \mathrm{~V}$
3 $\frac{\pi}{2} \times 10^{-2} \mathrm{~V}$
4 None of these
Electro Magnetic Induction

154689 The loop shown moves with a velocity $v$ in a uniform magnetic field of magnitude $B$, directed into the paper. The potential difference between $P$ and $Q$ is e. Then :

1 $\mathrm{e}=\frac{1}{2} \mathrm{Blv}$
2 $\mathrm{e}=$ Blv
3 $\mathrm{P}$ is negative with respect to $\mathrm{Q}$
4 $Q$ is positive with respect to $P$.
Electro Magnetic Induction

154690 A square loop of wire of side $5 \mathrm{~cm}$ is lying on a horizontal table. An electromagnet, above and to one side of the loop is turned on, causing a uniform magnetic field downward at an angle of $60^{\circ}$ to the vertical as shown in the figure, The magnetic induction is $0.50 \mathrm{~T}$. The average induced emf in the loop, if the field increases from zero to its final value in $0.2 \mathrm{~s}$ is

1 $5.4 \times 10^{-3} \mathrm{~V}$
2 $3.12 \times 10^{-3} \mathrm{~V}$
3 $0.25 \times 10^{-3} \mathrm{~V}$
4 zero
Electro Magnetic Induction

154686 A conducting $\operatorname{rod} \mathrm{AB}$ moves parallel to $\mathrm{X}$-axis in a uniform magnetic field, pointing in the positive z-direction. The end $A$ of the rod gets

1 positively charged
2 negatively charged
3 neutral
4 first positively charged and then negatively charged
Electro Magnetic Induction

154685 The distance between rails is $2 \mathrm{~m}$, which is parallel to earth magnetic meridian. Vertical component of earth magnetic field is $1.25 \times 10^{-4}$ tesla. If the speed of the train is $4 \mathrm{~m} / \mathrm{s}$, then induced emf across the axle is

1 $10^{-4} \mathrm{~V}$
2 $10^{-2} \mathrm{~V}$
3 $10^{-1} \mathrm{~V}$
4 $10^{-3} \mathrm{~V}$
Electro Magnetic Induction

154687 A disc of radius $0.1 \mathrm{~m}$ is rotating with a frequency $10 \mathrm{rev} / \mathrm{s}$ in a normal magnetic field of strength $0.1 \mathrm{~T}$. Net induced emf is

1 $2 \pi \times 10^{-2} \mathrm{~V}$
2 $\pi \times 10^{-2} \mathrm{~V}$
3 $\frac{\pi}{2} \times 10^{-2} \mathrm{~V}$
4 None of these
Electro Magnetic Induction

154689 The loop shown moves with a velocity $v$ in a uniform magnetic field of magnitude $B$, directed into the paper. The potential difference between $P$ and $Q$ is e. Then :

1 $\mathrm{e}=\frac{1}{2} \mathrm{Blv}$
2 $\mathrm{e}=$ Blv
3 $\mathrm{P}$ is negative with respect to $\mathrm{Q}$
4 $Q$ is positive with respect to $P$.
Electro Magnetic Induction

154690 A square loop of wire of side $5 \mathrm{~cm}$ is lying on a horizontal table. An electromagnet, above and to one side of the loop is turned on, causing a uniform magnetic field downward at an angle of $60^{\circ}$ to the vertical as shown in the figure, The magnetic induction is $0.50 \mathrm{~T}$. The average induced emf in the loop, if the field increases from zero to its final value in $0.2 \mathrm{~s}$ is

1 $5.4 \times 10^{-3} \mathrm{~V}$
2 $3.12 \times 10^{-3} \mathrm{~V}$
3 $0.25 \times 10^{-3} \mathrm{~V}$
4 zero
Electro Magnetic Induction

154686 A conducting $\operatorname{rod} \mathrm{AB}$ moves parallel to $\mathrm{X}$-axis in a uniform magnetic field, pointing in the positive z-direction. The end $A$ of the rod gets

1 positively charged
2 negatively charged
3 neutral
4 first positively charged and then negatively charged
Electro Magnetic Induction

154685 The distance between rails is $2 \mathrm{~m}$, which is parallel to earth magnetic meridian. Vertical component of earth magnetic field is $1.25 \times 10^{-4}$ tesla. If the speed of the train is $4 \mathrm{~m} / \mathrm{s}$, then induced emf across the axle is

1 $10^{-4} \mathrm{~V}$
2 $10^{-2} \mathrm{~V}$
3 $10^{-1} \mathrm{~V}$
4 $10^{-3} \mathrm{~V}$
Electro Magnetic Induction

154687 A disc of radius $0.1 \mathrm{~m}$ is rotating with a frequency $10 \mathrm{rev} / \mathrm{s}$ in a normal magnetic field of strength $0.1 \mathrm{~T}$. Net induced emf is

1 $2 \pi \times 10^{-2} \mathrm{~V}$
2 $\pi \times 10^{-2} \mathrm{~V}$
3 $\frac{\pi}{2} \times 10^{-2} \mathrm{~V}$
4 None of these
Electro Magnetic Induction

154689 The loop shown moves with a velocity $v$ in a uniform magnetic field of magnitude $B$, directed into the paper. The potential difference between $P$ and $Q$ is e. Then :

1 $\mathrm{e}=\frac{1}{2} \mathrm{Blv}$
2 $\mathrm{e}=$ Blv
3 $\mathrm{P}$ is negative with respect to $\mathrm{Q}$
4 $Q$ is positive with respect to $P$.
Electro Magnetic Induction

154690 A square loop of wire of side $5 \mathrm{~cm}$ is lying on a horizontal table. An electromagnet, above and to one side of the loop is turned on, causing a uniform magnetic field downward at an angle of $60^{\circ}$ to the vertical as shown in the figure, The magnetic induction is $0.50 \mathrm{~T}$. The average induced emf in the loop, if the field increases from zero to its final value in $0.2 \mathrm{~s}$ is

1 $5.4 \times 10^{-3} \mathrm{~V}$
2 $3.12 \times 10^{-3} \mathrm{~V}$
3 $0.25 \times 10^{-3} \mathrm{~V}$
4 zero
Electro Magnetic Induction

154686 A conducting $\operatorname{rod} \mathrm{AB}$ moves parallel to $\mathrm{X}$-axis in a uniform magnetic field, pointing in the positive z-direction. The end $A$ of the rod gets

1 positively charged
2 negatively charged
3 neutral
4 first positively charged and then negatively charged
Electro Magnetic Induction

154685 The distance between rails is $2 \mathrm{~m}$, which is parallel to earth magnetic meridian. Vertical component of earth magnetic field is $1.25 \times 10^{-4}$ tesla. If the speed of the train is $4 \mathrm{~m} / \mathrm{s}$, then induced emf across the axle is

1 $10^{-4} \mathrm{~V}$
2 $10^{-2} \mathrm{~V}$
3 $10^{-1} \mathrm{~V}$
4 $10^{-3} \mathrm{~V}$
Electro Magnetic Induction

154687 A disc of radius $0.1 \mathrm{~m}$ is rotating with a frequency $10 \mathrm{rev} / \mathrm{s}$ in a normal magnetic field of strength $0.1 \mathrm{~T}$. Net induced emf is

1 $2 \pi \times 10^{-2} \mathrm{~V}$
2 $\pi \times 10^{-2} \mathrm{~V}$
3 $\frac{\pi}{2} \times 10^{-2} \mathrm{~V}$
4 None of these
Electro Magnetic Induction

154689 The loop shown moves with a velocity $v$ in a uniform magnetic field of magnitude $B$, directed into the paper. The potential difference between $P$ and $Q$ is e. Then :

1 $\mathrm{e}=\frac{1}{2} \mathrm{Blv}$
2 $\mathrm{e}=$ Blv
3 $\mathrm{P}$ is negative with respect to $\mathrm{Q}$
4 $Q$ is positive with respect to $P$.
Electro Magnetic Induction

154690 A square loop of wire of side $5 \mathrm{~cm}$ is lying on a horizontal table. An electromagnet, above and to one side of the loop is turned on, causing a uniform magnetic field downward at an angle of $60^{\circ}$ to the vertical as shown in the figure, The magnetic induction is $0.50 \mathrm{~T}$. The average induced emf in the loop, if the field increases from zero to its final value in $0.2 \mathrm{~s}$ is

1 $5.4 \times 10^{-3} \mathrm{~V}$
2 $3.12 \times 10^{-3} \mathrm{~V}$
3 $0.25 \times 10^{-3} \mathrm{~V}$
4 zero
Electro Magnetic Induction

154686 A conducting $\operatorname{rod} \mathrm{AB}$ moves parallel to $\mathrm{X}$-axis in a uniform magnetic field, pointing in the positive z-direction. The end $A$ of the rod gets

1 positively charged
2 negatively charged
3 neutral
4 first positively charged and then negatively charged