00. Magnet and Magnetic Dipole
Magnetism and Matter

154087 When the radius of a circular current carrying coil is doubled and current in it is halved, the magnetic dipole moment of coil originally 4 units become.

1 18 unit
2 16 unit
3 8 unit
4 4 unit
Magnetism and Matter

154089 At a certain place a magnet makes 30 oscillations per minute. At another place where the magnetic field is double, its time period will be

1 $4 \mathrm{~s}$
2 $2 \mathrm{~s}$
3 $\frac{1}{2} \mathrm{~s}$
4 $\sqrt{2} \mathrm{~s}$
Magnetism and Matter

154090 The magnetic needle of a vibration magnetometer makes 12 oscillations per minute in the horizontal component of earth's magnetic field. When an external short bar magnet is placed at some distance along the axis of the needle in the same line, it makes $\mathbf{1 5}$ oscillations per minute. If the poles of the bar magnet are interchanged, the number of oscillations it will makes per minute is

1 $\sqrt{61}$
2 $\sqrt{63}$
3 $\sqrt{65}$
4 $\sqrt{67}$
Magnetism and Matter

154091 A magnet freely suspended in a vibration magnetometer makes 40 oscillations per minute at place $A$ and 20 oscillations per minute at a place B. If the horizontal component of earth's magnetic field at $A$ is $36 \times 10^{-6} \mathrm{~T}$, then its value at $B$ is

1 $30 \times 10^{-6} \mathrm{~T}$
2 $9 \times 10^{-6} \mathrm{~T}$
3 $144 \times 10^{-6} \mathrm{~T}$
4 $288 \times 10^{-6} \mathrm{~T}$
Magnetism and Matter

154087 When the radius of a circular current carrying coil is doubled and current in it is halved, the magnetic dipole moment of coil originally 4 units become.

1 18 unit
2 16 unit
3 8 unit
4 4 unit
Magnetism and Matter

154089 At a certain place a magnet makes 30 oscillations per minute. At another place where the magnetic field is double, its time period will be

1 $4 \mathrm{~s}$
2 $2 \mathrm{~s}$
3 $\frac{1}{2} \mathrm{~s}$
4 $\sqrt{2} \mathrm{~s}$
Magnetism and Matter

154090 The magnetic needle of a vibration magnetometer makes 12 oscillations per minute in the horizontal component of earth's magnetic field. When an external short bar magnet is placed at some distance along the axis of the needle in the same line, it makes $\mathbf{1 5}$ oscillations per minute. If the poles of the bar magnet are interchanged, the number of oscillations it will makes per minute is

1 $\sqrt{61}$
2 $\sqrt{63}$
3 $\sqrt{65}$
4 $\sqrt{67}$
Magnetism and Matter

154091 A magnet freely suspended in a vibration magnetometer makes 40 oscillations per minute at place $A$ and 20 oscillations per minute at a place B. If the horizontal component of earth's magnetic field at $A$ is $36 \times 10^{-6} \mathrm{~T}$, then its value at $B$ is

1 $30 \times 10^{-6} \mathrm{~T}$
2 $9 \times 10^{-6} \mathrm{~T}$
3 $144 \times 10^{-6} \mathrm{~T}$
4 $288 \times 10^{-6} \mathrm{~T}$
Magnetism and Matter

154087 When the radius of a circular current carrying coil is doubled and current in it is halved, the magnetic dipole moment of coil originally 4 units become.

1 18 unit
2 16 unit
3 8 unit
4 4 unit
Magnetism and Matter

154089 At a certain place a magnet makes 30 oscillations per minute. At another place where the magnetic field is double, its time period will be

1 $4 \mathrm{~s}$
2 $2 \mathrm{~s}$
3 $\frac{1}{2} \mathrm{~s}$
4 $\sqrt{2} \mathrm{~s}$
Magnetism and Matter

154090 The magnetic needle of a vibration magnetometer makes 12 oscillations per minute in the horizontal component of earth's magnetic field. When an external short bar magnet is placed at some distance along the axis of the needle in the same line, it makes $\mathbf{1 5}$ oscillations per minute. If the poles of the bar magnet are interchanged, the number of oscillations it will makes per minute is

1 $\sqrt{61}$
2 $\sqrt{63}$
3 $\sqrt{65}$
4 $\sqrt{67}$
Magnetism and Matter

154091 A magnet freely suspended in a vibration magnetometer makes 40 oscillations per minute at place $A$ and 20 oscillations per minute at a place B. If the horizontal component of earth's magnetic field at $A$ is $36 \times 10^{-6} \mathrm{~T}$, then its value at $B$ is

1 $30 \times 10^{-6} \mathrm{~T}$
2 $9 \times 10^{-6} \mathrm{~T}$
3 $144 \times 10^{-6} \mathrm{~T}$
4 $288 \times 10^{-6} \mathrm{~T}$
Magnetism and Matter

154087 When the radius of a circular current carrying coil is doubled and current in it is halved, the magnetic dipole moment of coil originally 4 units become.

1 18 unit
2 16 unit
3 8 unit
4 4 unit
Magnetism and Matter

154089 At a certain place a magnet makes 30 oscillations per minute. At another place where the magnetic field is double, its time period will be

1 $4 \mathrm{~s}$
2 $2 \mathrm{~s}$
3 $\frac{1}{2} \mathrm{~s}$
4 $\sqrt{2} \mathrm{~s}$
Magnetism and Matter

154090 The magnetic needle of a vibration magnetometer makes 12 oscillations per minute in the horizontal component of earth's magnetic field. When an external short bar magnet is placed at some distance along the axis of the needle in the same line, it makes $\mathbf{1 5}$ oscillations per minute. If the poles of the bar magnet are interchanged, the number of oscillations it will makes per minute is

1 $\sqrt{61}$
2 $\sqrt{63}$
3 $\sqrt{65}$
4 $\sqrt{67}$
Magnetism and Matter

154091 A magnet freely suspended in a vibration magnetometer makes 40 oscillations per minute at place $A$ and 20 oscillations per minute at a place B. If the horizontal component of earth's magnetic field at $A$ is $36 \times 10^{-6} \mathrm{~T}$, then its value at $B$ is

1 $30 \times 10^{-6} \mathrm{~T}$
2 $9 \times 10^{-6} \mathrm{~T}$
3 $144 \times 10^{-6} \mathrm{~T}$
4 $288 \times 10^{-6} \mathrm{~T}$