D Paramagnetic material have permanent dipole moment Diamagnetic substances no have any unpaired electron. Ferromagnetic substance atom have permanent magnetic dipole moment. So, all of the above statements are correct.
SCRA-2015
Magnetism and Matter
154404
Current flows through a thick long straight wire such that the current density is uniform over the cross-section of the wire. The magnetic induction $B$ inside the wire at a distance $r$ from the axis is
1 proportional to $r$
2 inversely proportional to $r$
3 inversely proportional to $r^{2}$
4 uniform throughout the cross section of the wire
Explanation:
A Magnetic field inside a cylindrical wire which radii $\mathrm{R}$ at distance $\mathrm{r}$ $\mathrm{B}_{\text {inside }}=\frac{\mu_{\mathrm{o}} \mathrm{Ir}}{2 \pi \mathrm{R}^{2}}$ So, $\mathrm{B}_{\text {inside }} \propto \mathrm{r}$
SCRA-2013
Magnetism and Matter
154405
A bar magnet is suspended from the middle point in a uniform magnetic field. The couple acting on the bar magnet is minimum when the magnet is
1 parallel to the field
2 perpendicular to the field
3 at an angle of $45^{\circ}$ to the field
4 at an angle of $60^{\circ}$ to the field
Explanation:
A When a bar magnet is suspended from middle point in a uniform magnetic field then torque $\tau=\mathrm{MB} \sin \theta$ $\tau \propto \sin \theta$ Torque is minimum when $\theta=0^{\circ}$ So, magnet suspended parallel to field.
SCRA-2012
Magnetism and Matter
154408
Two long wires are set parallel to each other. Each carries a current (i) in the same direction and the separation between them is $2 r$. What is the intensity of magnetic field midway between them?
1 $\frac{4 \mathrm{i}}{\mathrm{r}}$
2 $\frac{2 \mathrm{i}}{\mathrm{r}}$
3 $\frac{\mathrm{i}}{\mathrm{r}}$
4 Zero
Explanation:
D The magnetic field produced at the midpoint by the current flowing in the same direction in the two parallel wire will be equal in magnitude but opposite in direction so the resultant magnetic field at mid point will be zero. So, option (d) are correct
D Paramagnetic material have permanent dipole moment Diamagnetic substances no have any unpaired electron. Ferromagnetic substance atom have permanent magnetic dipole moment. So, all of the above statements are correct.
SCRA-2015
Magnetism and Matter
154404
Current flows through a thick long straight wire such that the current density is uniform over the cross-section of the wire. The magnetic induction $B$ inside the wire at a distance $r$ from the axis is
1 proportional to $r$
2 inversely proportional to $r$
3 inversely proportional to $r^{2}$
4 uniform throughout the cross section of the wire
Explanation:
A Magnetic field inside a cylindrical wire which radii $\mathrm{R}$ at distance $\mathrm{r}$ $\mathrm{B}_{\text {inside }}=\frac{\mu_{\mathrm{o}} \mathrm{Ir}}{2 \pi \mathrm{R}^{2}}$ So, $\mathrm{B}_{\text {inside }} \propto \mathrm{r}$
SCRA-2013
Magnetism and Matter
154405
A bar magnet is suspended from the middle point in a uniform magnetic field. The couple acting on the bar magnet is minimum when the magnet is
1 parallel to the field
2 perpendicular to the field
3 at an angle of $45^{\circ}$ to the field
4 at an angle of $60^{\circ}$ to the field
Explanation:
A When a bar magnet is suspended from middle point in a uniform magnetic field then torque $\tau=\mathrm{MB} \sin \theta$ $\tau \propto \sin \theta$ Torque is minimum when $\theta=0^{\circ}$ So, magnet suspended parallel to field.
SCRA-2012
Magnetism and Matter
154408
Two long wires are set parallel to each other. Each carries a current (i) in the same direction and the separation between them is $2 r$. What is the intensity of magnetic field midway between them?
1 $\frac{4 \mathrm{i}}{\mathrm{r}}$
2 $\frac{2 \mathrm{i}}{\mathrm{r}}$
3 $\frac{\mathrm{i}}{\mathrm{r}}$
4 Zero
Explanation:
D The magnetic field produced at the midpoint by the current flowing in the same direction in the two parallel wire will be equal in magnitude but opposite in direction so the resultant magnetic field at mid point will be zero. So, option (d) are correct
D Paramagnetic material have permanent dipole moment Diamagnetic substances no have any unpaired electron. Ferromagnetic substance atom have permanent magnetic dipole moment. So, all of the above statements are correct.
SCRA-2015
Magnetism and Matter
154404
Current flows through a thick long straight wire such that the current density is uniform over the cross-section of the wire. The magnetic induction $B$ inside the wire at a distance $r$ from the axis is
1 proportional to $r$
2 inversely proportional to $r$
3 inversely proportional to $r^{2}$
4 uniform throughout the cross section of the wire
Explanation:
A Magnetic field inside a cylindrical wire which radii $\mathrm{R}$ at distance $\mathrm{r}$ $\mathrm{B}_{\text {inside }}=\frac{\mu_{\mathrm{o}} \mathrm{Ir}}{2 \pi \mathrm{R}^{2}}$ So, $\mathrm{B}_{\text {inside }} \propto \mathrm{r}$
SCRA-2013
Magnetism and Matter
154405
A bar magnet is suspended from the middle point in a uniform magnetic field. The couple acting on the bar magnet is minimum when the magnet is
1 parallel to the field
2 perpendicular to the field
3 at an angle of $45^{\circ}$ to the field
4 at an angle of $60^{\circ}$ to the field
Explanation:
A When a bar magnet is suspended from middle point in a uniform magnetic field then torque $\tau=\mathrm{MB} \sin \theta$ $\tau \propto \sin \theta$ Torque is minimum when $\theta=0^{\circ}$ So, magnet suspended parallel to field.
SCRA-2012
Magnetism and Matter
154408
Two long wires are set parallel to each other. Each carries a current (i) in the same direction and the separation between them is $2 r$. What is the intensity of magnetic field midway between them?
1 $\frac{4 \mathrm{i}}{\mathrm{r}}$
2 $\frac{2 \mathrm{i}}{\mathrm{r}}$
3 $\frac{\mathrm{i}}{\mathrm{r}}$
4 Zero
Explanation:
D The magnetic field produced at the midpoint by the current flowing in the same direction in the two parallel wire will be equal in magnitude but opposite in direction so the resultant magnetic field at mid point will be zero. So, option (d) are correct
D Paramagnetic material have permanent dipole moment Diamagnetic substances no have any unpaired electron. Ferromagnetic substance atom have permanent magnetic dipole moment. So, all of the above statements are correct.
SCRA-2015
Magnetism and Matter
154404
Current flows through a thick long straight wire such that the current density is uniform over the cross-section of the wire. The magnetic induction $B$ inside the wire at a distance $r$ from the axis is
1 proportional to $r$
2 inversely proportional to $r$
3 inversely proportional to $r^{2}$
4 uniform throughout the cross section of the wire
Explanation:
A Magnetic field inside a cylindrical wire which radii $\mathrm{R}$ at distance $\mathrm{r}$ $\mathrm{B}_{\text {inside }}=\frac{\mu_{\mathrm{o}} \mathrm{Ir}}{2 \pi \mathrm{R}^{2}}$ So, $\mathrm{B}_{\text {inside }} \propto \mathrm{r}$
SCRA-2013
Magnetism and Matter
154405
A bar magnet is suspended from the middle point in a uniform magnetic field. The couple acting on the bar magnet is minimum when the magnet is
1 parallel to the field
2 perpendicular to the field
3 at an angle of $45^{\circ}$ to the field
4 at an angle of $60^{\circ}$ to the field
Explanation:
A When a bar magnet is suspended from middle point in a uniform magnetic field then torque $\tau=\mathrm{MB} \sin \theta$ $\tau \propto \sin \theta$ Torque is minimum when $\theta=0^{\circ}$ So, magnet suspended parallel to field.
SCRA-2012
Magnetism and Matter
154408
Two long wires are set parallel to each other. Each carries a current (i) in the same direction and the separation between them is $2 r$. What is the intensity of magnetic field midway between them?
1 $\frac{4 \mathrm{i}}{\mathrm{r}}$
2 $\frac{2 \mathrm{i}}{\mathrm{r}}$
3 $\frac{\mathrm{i}}{\mathrm{r}}$
4 Zero
Explanation:
D The magnetic field produced at the midpoint by the current flowing in the same direction in the two parallel wire will be equal in magnitude but opposite in direction so the resultant magnetic field at mid point will be zero. So, option (d) are correct
