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

153213 A circular loop of radius $r$ of conducting wire connected with a voltage source of zero internal resistance produces a magnetic field $B$ at its centre. If instead, a circular loop radius $2 \mathbf{r}$, made of same material, having the same crosssection is connected to the same voltage source, what will be the magnetic field at its centre?

1 $\frac{B}{2}$
2 $\frac{B}{4}$
3 $2 \mathrm{~B}$
4 $\mathrm{B}$
Moving Charges & Magnetism

153214 A straight wire carrying current $I$ is made into a circular loop. If $M$ is the magnetic moment associated with the loop, then the length of the wire is-

1 $\mathrm{L}=\sqrt{\frac{\mathrm{M}}{4 \pi I}}$
2 $\mathrm{L}=\mathrm{M} \sqrt{\frac{2 \pi}{\mathrm{L}}}$
3 $\mathrm{L}=\sqrt{\frac{4 \pi \mathrm{M}}{I}}$
4 $\mathrm{L}=\sqrt{4 \pi \mathrm{M} \cdot I}$
Moving Charges & Magnetism

153215 The strength of the magnetic field at a point distant $r$ near a long straight current carrying wire is $B$. The field at a distance $\frac{r}{2}$ will be

1 $\frac{B}{2}$
2 $2 \mathrm{~B}$
3 $\frac{\mathrm{B}}{4}$
4 $4 \mathrm{~B}$
Moving Charges & Magnetism

153217 The magnetic field due to current carrying circular coil loop of radius $6 \mathrm{~cm}$ at a point on axis at a distance of $8 \mathrm{~cm}$ from the center is 54 $\mu \mathrm{T}$. What is the value at centre of loop?

1 $75 \mu \mathrm{T}$
2 $125 \mu \mathrm{T}$
3 $150 \mu \mathrm{T}$
4 $250 \mu \mathrm{T}$
Moving Charges & Magnetism

153213 A circular loop of radius $r$ of conducting wire connected with a voltage source of zero internal resistance produces a magnetic field $B$ at its centre. If instead, a circular loop radius $2 \mathbf{r}$, made of same material, having the same crosssection is connected to the same voltage source, what will be the magnetic field at its centre?

1 $\frac{B}{2}$
2 $\frac{B}{4}$
3 $2 \mathrm{~B}$
4 $\mathrm{B}$
Moving Charges & Magnetism

153214 A straight wire carrying current $I$ is made into a circular loop. If $M$ is the magnetic moment associated with the loop, then the length of the wire is-

1 $\mathrm{L}=\sqrt{\frac{\mathrm{M}}{4 \pi I}}$
2 $\mathrm{L}=\mathrm{M} \sqrt{\frac{2 \pi}{\mathrm{L}}}$
3 $\mathrm{L}=\sqrt{\frac{4 \pi \mathrm{M}}{I}}$
4 $\mathrm{L}=\sqrt{4 \pi \mathrm{M} \cdot I}$
Moving Charges & Magnetism

153215 The strength of the magnetic field at a point distant $r$ near a long straight current carrying wire is $B$. The field at a distance $\frac{r}{2}$ will be

1 $\frac{B}{2}$
2 $2 \mathrm{~B}$
3 $\frac{\mathrm{B}}{4}$
4 $4 \mathrm{~B}$
Moving Charges & Magnetism

153217 The magnetic field due to current carrying circular coil loop of radius $6 \mathrm{~cm}$ at a point on axis at a distance of $8 \mathrm{~cm}$ from the center is 54 $\mu \mathrm{T}$. What is the value at centre of loop?

1 $75 \mu \mathrm{T}$
2 $125 \mu \mathrm{T}$
3 $150 \mu \mathrm{T}$
4 $250 \mu \mathrm{T}$
Moving Charges & Magnetism

153213 A circular loop of radius $r$ of conducting wire connected with a voltage source of zero internal resistance produces a magnetic field $B$ at its centre. If instead, a circular loop radius $2 \mathbf{r}$, made of same material, having the same crosssection is connected to the same voltage source, what will be the magnetic field at its centre?

1 $\frac{B}{2}$
2 $\frac{B}{4}$
3 $2 \mathrm{~B}$
4 $\mathrm{B}$
Moving Charges & Magnetism

153214 A straight wire carrying current $I$ is made into a circular loop. If $M$ is the magnetic moment associated with the loop, then the length of the wire is-

1 $\mathrm{L}=\sqrt{\frac{\mathrm{M}}{4 \pi I}}$
2 $\mathrm{L}=\mathrm{M} \sqrt{\frac{2 \pi}{\mathrm{L}}}$
3 $\mathrm{L}=\sqrt{\frac{4 \pi \mathrm{M}}{I}}$
4 $\mathrm{L}=\sqrt{4 \pi \mathrm{M} \cdot I}$
Moving Charges & Magnetism

153215 The strength of the magnetic field at a point distant $r$ near a long straight current carrying wire is $B$. The field at a distance $\frac{r}{2}$ will be

1 $\frac{B}{2}$
2 $2 \mathrm{~B}$
3 $\frac{\mathrm{B}}{4}$
4 $4 \mathrm{~B}$
Moving Charges & Magnetism

153217 The magnetic field due to current carrying circular coil loop of radius $6 \mathrm{~cm}$ at a point on axis at a distance of $8 \mathrm{~cm}$ from the center is 54 $\mu \mathrm{T}$. What is the value at centre of loop?

1 $75 \mu \mathrm{T}$
2 $125 \mu \mathrm{T}$
3 $150 \mu \mathrm{T}$
4 $250 \mu \mathrm{T}$
Moving Charges & Magnetism

153213 A circular loop of radius $r$ of conducting wire connected with a voltage source of zero internal resistance produces a magnetic field $B$ at its centre. If instead, a circular loop radius $2 \mathbf{r}$, made of same material, having the same crosssection is connected to the same voltage source, what will be the magnetic field at its centre?

1 $\frac{B}{2}$
2 $\frac{B}{4}$
3 $2 \mathrm{~B}$
4 $\mathrm{B}$
Moving Charges & Magnetism

153214 A straight wire carrying current $I$ is made into a circular loop. If $M$ is the magnetic moment associated with the loop, then the length of the wire is-

1 $\mathrm{L}=\sqrt{\frac{\mathrm{M}}{4 \pi I}}$
2 $\mathrm{L}=\mathrm{M} \sqrt{\frac{2 \pi}{\mathrm{L}}}$
3 $\mathrm{L}=\sqrt{\frac{4 \pi \mathrm{M}}{I}}$
4 $\mathrm{L}=\sqrt{4 \pi \mathrm{M} \cdot I}$
Moving Charges & Magnetism

153215 The strength of the magnetic field at a point distant $r$ near a long straight current carrying wire is $B$. The field at a distance $\frac{r}{2}$ will be

1 $\frac{B}{2}$
2 $2 \mathrm{~B}$
3 $\frac{\mathrm{B}}{4}$
4 $4 \mathrm{~B}$
Moving Charges & Magnetism

153217 The magnetic field due to current carrying circular coil loop of radius $6 \mathrm{~cm}$ at a point on axis at a distance of $8 \mathrm{~cm}$ from the center is 54 $\mu \mathrm{T}$. What is the value at centre of loop?

1 $75 \mu \mathrm{T}$
2 $125 \mu \mathrm{T}$
3 $150 \mu \mathrm{T}$
4 $250 \mu \mathrm{T}$