00. Biot-Savart's Law and Magnetic Field, Lorentz Force
Moving Charges & Magnetism

153133 The electric current in a circular coil of 2 turns produces a magnetic induction $B_{1}$ at its centre. The coil is unwound and is rewound into a circular coil of 5 turns and the same current produces a magnetic induction $B_{2}$ at its centre.
The ratio of $\frac{B_{2}}{B_{1}}$ is :

1 $\frac{5}{2}$
2 $\frac{25}{4}$
3 $\frac{5}{4}$
4 $\frac{25}{2}$
Moving Charges & Magnetism

153136 A current carrying loop ABCD has two circular ares $A D$ and $B C$ with radius $1 \mathrm{~cm}$ and $2 \mathrm{~cm}$ respectively as shown in the figure. The two ares $\mathrm{AD}$ and $\mathrm{BC}$ subtend a common angle $30^{\circ}$ at the centre $O$. If the current flowing in the loop is $\frac{1.2}{\pi} \mathrm{A}$ then the magnitude of net magnetic field at $O$ is (Given $\mu_{0}=4 \pi \times 10^{-7}$ )

1 $0.5 \mu \mathrm{T}$
2 $3 \mu \mathrm{T}$
3 $1 \mu \mathrm{T}$
4 $1.5 \mu \mathrm{T}$
Moving Charges & Magnetism

153137 Two infinite parallel wires separated by $1 \mathrm{~m}$ carry current $I$ in the same direction. The magnetic field at a point $50 \mathrm{~cm}$ from each wire is

1 $\frac{\mu_{0} I}{2 \pi}$
2 $\frac{2 \mu_{0} \mathrm{I}}{3}$
3 $\frac{\mu_{0} \mathrm{I}}{\pi}$
4 0
Moving Charges & Magnetism

153138 Statement (I) : A bar magnet exerts a torque on itself due to its own field.
Statement (II) : Magnet field lines can be entirely confined within the core of toroid.
Statement (III) : The net magnetic flux through any closed surface is zero.
Which of the following is correct?

1 Statement I, II, III are true
2 Statement I, III are true but the Statement II is false
3 Statement I, II are true but the Statement III is false
4 Statement II, III are true but the Statement I is false
Moving Charges & Magnetism

153133 The electric current in a circular coil of 2 turns produces a magnetic induction $B_{1}$ at its centre. The coil is unwound and is rewound into a circular coil of 5 turns and the same current produces a magnetic induction $B_{2}$ at its centre.
The ratio of $\frac{B_{2}}{B_{1}}$ is :

1 $\frac{5}{2}$
2 $\frac{25}{4}$
3 $\frac{5}{4}$
4 $\frac{25}{2}$
Moving Charges & Magnetism

153136 A current carrying loop ABCD has two circular ares $A D$ and $B C$ with radius $1 \mathrm{~cm}$ and $2 \mathrm{~cm}$ respectively as shown in the figure. The two ares $\mathrm{AD}$ and $\mathrm{BC}$ subtend a common angle $30^{\circ}$ at the centre $O$. If the current flowing in the loop is $\frac{1.2}{\pi} \mathrm{A}$ then the magnitude of net magnetic field at $O$ is (Given $\mu_{0}=4 \pi \times 10^{-7}$ )

1 $0.5 \mu \mathrm{T}$
2 $3 \mu \mathrm{T}$
3 $1 \mu \mathrm{T}$
4 $1.5 \mu \mathrm{T}$
Moving Charges & Magnetism

153137 Two infinite parallel wires separated by $1 \mathrm{~m}$ carry current $I$ in the same direction. The magnetic field at a point $50 \mathrm{~cm}$ from each wire is

1 $\frac{\mu_{0} I}{2 \pi}$
2 $\frac{2 \mu_{0} \mathrm{I}}{3}$
3 $\frac{\mu_{0} \mathrm{I}}{\pi}$
4 0
Moving Charges & Magnetism

153138 Statement (I) : A bar magnet exerts a torque on itself due to its own field.
Statement (II) : Magnet field lines can be entirely confined within the core of toroid.
Statement (III) : The net magnetic flux through any closed surface is zero.
Which of the following is correct?

1 Statement I, II, III are true
2 Statement I, III are true but the Statement II is false
3 Statement I, II are true but the Statement III is false
4 Statement II, III are true but the Statement I is false
Moving Charges & Magnetism

153133 The electric current in a circular coil of 2 turns produces a magnetic induction $B_{1}$ at its centre. The coil is unwound and is rewound into a circular coil of 5 turns and the same current produces a magnetic induction $B_{2}$ at its centre.
The ratio of $\frac{B_{2}}{B_{1}}$ is :

1 $\frac{5}{2}$
2 $\frac{25}{4}$
3 $\frac{5}{4}$
4 $\frac{25}{2}$
Moving Charges & Magnetism

153136 A current carrying loop ABCD has two circular ares $A D$ and $B C$ with radius $1 \mathrm{~cm}$ and $2 \mathrm{~cm}$ respectively as shown in the figure. The two ares $\mathrm{AD}$ and $\mathrm{BC}$ subtend a common angle $30^{\circ}$ at the centre $O$. If the current flowing in the loop is $\frac{1.2}{\pi} \mathrm{A}$ then the magnitude of net magnetic field at $O$ is (Given $\mu_{0}=4 \pi \times 10^{-7}$ )

1 $0.5 \mu \mathrm{T}$
2 $3 \mu \mathrm{T}$
3 $1 \mu \mathrm{T}$
4 $1.5 \mu \mathrm{T}$
Moving Charges & Magnetism

153137 Two infinite parallel wires separated by $1 \mathrm{~m}$ carry current $I$ in the same direction. The magnetic field at a point $50 \mathrm{~cm}$ from each wire is

1 $\frac{\mu_{0} I}{2 \pi}$
2 $\frac{2 \mu_{0} \mathrm{I}}{3}$
3 $\frac{\mu_{0} \mathrm{I}}{\pi}$
4 0
Moving Charges & Magnetism

153138 Statement (I) : A bar magnet exerts a torque on itself due to its own field.
Statement (II) : Magnet field lines can be entirely confined within the core of toroid.
Statement (III) : The net magnetic flux through any closed surface is zero.
Which of the following is correct?

1 Statement I, II, III are true
2 Statement I, III are true but the Statement II is false
3 Statement I, II are true but the Statement III is false
4 Statement II, III are true but the Statement I is false
Moving Charges & Magnetism

153133 The electric current in a circular coil of 2 turns produces a magnetic induction $B_{1}$ at its centre. The coil is unwound and is rewound into a circular coil of 5 turns and the same current produces a magnetic induction $B_{2}$ at its centre.
The ratio of $\frac{B_{2}}{B_{1}}$ is :

1 $\frac{5}{2}$
2 $\frac{25}{4}$
3 $\frac{5}{4}$
4 $\frac{25}{2}$
Moving Charges & Magnetism

153136 A current carrying loop ABCD has two circular ares $A D$ and $B C$ with radius $1 \mathrm{~cm}$ and $2 \mathrm{~cm}$ respectively as shown in the figure. The two ares $\mathrm{AD}$ and $\mathrm{BC}$ subtend a common angle $30^{\circ}$ at the centre $O$. If the current flowing in the loop is $\frac{1.2}{\pi} \mathrm{A}$ then the magnitude of net magnetic field at $O$ is (Given $\mu_{0}=4 \pi \times 10^{-7}$ )

1 $0.5 \mu \mathrm{T}$
2 $3 \mu \mathrm{T}$
3 $1 \mu \mathrm{T}$
4 $1.5 \mu \mathrm{T}$
Moving Charges & Magnetism

153137 Two infinite parallel wires separated by $1 \mathrm{~m}$ carry current $I$ in the same direction. The magnetic field at a point $50 \mathrm{~cm}$ from each wire is

1 $\frac{\mu_{0} I}{2 \pi}$
2 $\frac{2 \mu_{0} \mathrm{I}}{3}$
3 $\frac{\mu_{0} \mathrm{I}}{\pi}$
4 0
Moving Charges & Magnetism

153138 Statement (I) : A bar magnet exerts a torque on itself due to its own field.
Statement (II) : Magnet field lines can be entirely confined within the core of toroid.
Statement (III) : The net magnetic flux through any closed surface is zero.
Which of the following is correct?

1 Statement I, II, III are true
2 Statement I, III are true but the Statement II is false
3 Statement I, II are true but the Statement III is false
4 Statement II, III are true but the Statement I is false