Magnetic Meridian

Q. The true value of angle of dip at a place is ${60}^{\circ }$, the apparent dip in a plane inclined at an angle of ${30}^{\circ }$ with magnetic meridian is

1. $Noneofthese$
2. $ta{n}^{-1}\frac{1}{2}$
   
3. $ta{n}^{-1}\left(2\right)$
   
4. $ta{n}^{-1}\left(\frac{2}{3}\right)$

Q. A dip circle is adjusted so that its needle moves freely in the magnetic meridian. In this position, the angle of dip is
​${40}^{\circ }$. Now the dip circle is rotated so that the plane in which the needle moves makes an angle of ​${30}^{\circ }$ with the magnetic meridian. In this position the needle will dip by an angle

1. $Lessthan{40}^{\circ }$
2. $Morethan{40}^{\circ }$
3. ${30}^{\circ }$
4. ${40}^{\circ }$

Q.

The flux linked with a coil at any instant t is given by $\mathrm{\varphi }=10{\mathrm{t}}^2-50\mathrm{t}+250$. The induced emf at $\mathrm{t}=3\mathrm{s}$ is

Q.

What is the angle of inclination?

1. The angle made by the Earths magnetic field with its horizontal component

2. The angle made by the magnetic meridian with geographic meridian

3. The angle made by the Earths magnetic field with its vertical component

4. The angle made by the Earths geographic meridian with its horizontal component

Q. A short bar magnet is kept in the earth's magnetic field with its north pole pointing geographic north. The magnetic moment of the short bar magnet is $0.4{\text{Am}}^2$. If earth's horizontal magnetic field is $4\times {10}^{-5}\text{T}$, then the distance between the null points is

Q. A short bar magnet of moment $6.75{\text{A-m}}^2$, produces a neutral point on its axis. If the horizontal component of earth's magnetic field is $5\times {10}^{-5}{\text{Wb/m}}^2$, then the distance of the neutral point should be

1. $10\text{cm}$
2. $20\text{cm}$
3. $30\text{cm}$
4. $40\text{cm}$

Q. Two identical bar magnets with a length 10 cm and weight 50 gm-weight are arranged freely with their like poles facing in a inverted vertical glass tube. The upper magnet hangs in the air above the lower one so that the distance between the nearest pole of the magnet is 3mm. Pole strength of the poles of each magnet will be

1. $6.64amp\times m$
2. $2amp\times m$
3. $10.25amp\times m$
4. $Noneofthese$

Q.

The angle of dip at the equator is ____.

Q. A short bar magnet is placed in the magnetic meridian of the earth with the north pole pointing north. Neutral points are found at a distance of $30\text{cm}$ from the magnet on the east - west line, drawn through the middle point of the magnet. The magnetic moment of the magnet in $\left({\text{Am}}^2\right)$ is close to
(Given $\frac{{\mu }_0}{4\pi }={10}^{-7}$ in SI units and $B_H$ = Horizontal component of earth's magnetic field = $3.6\times {10}^{-5}\text{T}$)

1. $4.9$
2. 
   $14.6$
3. $32.4$
4. $9.7$

Q.

What happens if the earths magnetic pole flips?

Q.

A house has a floor area of 112m², and has an outside wall that has an area of 28m². The earth’s magnetic field here has a horizontal component of $2.6\times {10}^{-5}T$ that points due north and a vertical component of $4.2\times {10}^{-5}T$ that points straight down, toward the earth. Determine the magnetic flux through the wall if the wall faces (a) north, and (b) east, and (c) also calculate the magnetic flux that passes through the floor.

Q.

Answer the following questions regarding earth’s magnetism:

(a) A vector needs three quantities for its specification. Name the three independent quantities conventionally used to specify the earth’s magnetic field.

(b) The angle of dip at a location in southern India is about 18º.

Would you expect a greater or smaller dip angle in Britain?

(c) If you made a map of magnetic field lines at Melbourne in Australia, would the lines seem to go into the ground or come out of the ground?

(d) In which direction would a compass free to move in the vertical plane point to, if located right on the geomagnetic north or south pole?

(e) The earth’s field, it is claimed, roughly approximates the field due to a dipole of magnetic moment 8 × 1022 J T⁻¹ located at its centre. Check the order of magnitude of this number in some way.

(f ) Geologists claim that besides the main magnetic N-S poles, there are several local poles on the earth’s surface oriented in different directions. How is such a thing possible at all?

Q. A compass needle which is allowed to move in a horizontal plane is taken to a geomagnetic pole. It

1. Will stay in its position, showing no movement
2. Will stay in north-west direction only
3. Will stay in north-south direction only
4. Will stay in east-west direction only

Q.

The equatorial meridian of a magnet ___________.

1. bisects the magnetic axis perpendicularly.

2. is parallel to the magnetic axis.

3. makes a certain angle with the magnetic equator.

4. contains both the pole of the magnet.

Q. A long horizontal metallic rod with length along the east-west direction is falling under gravity. The potentiol difference between its two ends will :

1. be zero
2. be constant
3. increase with time
4. decrease with time

Q. At a certain place, the horizontal component of the earth’s magnetic field is $B_0$ and the angle of dip is ${45}^{\circ }$. If the total intensity of the field at that place is $\sqrt{\alpha }{B}_0,$ then find $\alpha$.

Q. Magnetic meridian is a plane _____

1. Perpendicular to magnetic axis of Earth
2. Passing through the magnetic axis of Earth
3. Perpendicular to geographic axis of Earth
4. Passing through the geographic axis

Q. The magnetic north pole is not same as the geographic north because

1. Earth’s imaginary bar magnet inside is not aligned to geographic north south

2. Earth’s imaginary bar magnet inside is perfectly aligned to geographic north south

3. none of these

4. Earth does not produce magnetic field lines

Q. 99. A horizontal conducting rod10m long extending from east to west is falling with a speed of 5msec at right angles to the horizontal component of earth magnetic fied 0.3*10-4(zero point three multiplied by ten raised to the power minus four) find the instananeous value of emf induced in the rod

Q.

A boat is moving due East in a region where the earth's magnetic field is 5×10^-5 T due north and horizontal . The boat carries a vertical aerial 2m long. If the speed of the boat is 1.50m/s , what will be the magnitude of the induced emf in the wire of aerial !

Q. If a magnet is suspended at an angle ${30}^{\circ }$ to the magnetic meridian, it makes an angle of 45o with the horizontal. The real dip is

1. $ta{n}^{-1}\left(\frac{\sqrt{3}}{2}\right)\ast$
2. $ta{n}^{-1}\left(\sqrt{3}\right)$
3. $ta{n}^{-1}\left(\frac{\sqrt{3}}{2}\right)$
4. $ta{n}^{-1}\left(\frac{2}{\sqrt{3}}\right)$

Q.

The units of magnetic pole strength and magnetic dipole moment of a bar magnet are

1. A-m, JT^-1

2. JT^-1, A-m

3. JT^-1, Am^-1

4. Am^-1, JT^-1

Q. If a magnet is suspended at an angle ${30}^{\circ }$ to the magnetic meridian, it makes an angle of ${45}^{\circ }$ with the horizontal. The real dip is

1. $ta{n}^{-1}\left(\frac{\sqrt{3}}{2}\right)$
2. $ta{n}^{-1}\left(\sqrt{3}\right)$
3. $ta{n}^{-1}\left(\frac{\sqrt{3}}{2}\right)$
4. $ta{n}^{-1}\left(\frac{2}{\sqrt{3}}\right)$

Q. A compass needle which is allowed to move in a horizontal plane is taken to a geomagnetic pole. It

(a) will stay in north-south direction only
(b) will stay in east-west direction only
(c) will become rigid showing no movement
(d) will stay in any position

Q. A bar magnet is placed with its north pole towards geographic south. The neutral point will be

1. On the axial line
2. On the equatorial line
3. In-between axial and equatorial line
4. At ${30}^0$ with the axial line

Q. A dip circle is placed perpendicular to the magnetic meridian, then the magnetic needle will align

1. Vertically
2. In the direction of earths magnetic field
3. Perpendicular to earths magnetic field
4. Horizontally

Q. A projectile is projected with speed $u$ at an angle of ${60}^o$ with horizontal from the foot of an inclined plane. If the projectile hits the inclined plane horizontally, the range on inclined plane will be

1. $\frac{3u^2}{4g}$
2. $\frac{u^2\sqrt{21}}{2g}$
3. $\frac{u^2}{2\beta }$
4. $\frac{\sqrt{21}{u}^2}{8g}$

Q. A dip of circle is so set that it moves freely in the magnetic meridian. In this position, the angle of dip is ${40}^0$. Now, the dip circle is rotated so that the plane in which the needle moves makes an angle of ${30}^0$ with the magnetic meridian. In this position, the needle will dip by an angle of

1. ${30}^0$
2. ${40}^0$
3. More than ${40}^0$
4. Less than ${40}^0$

Q. 59.1.2m wide railways track is parallel to magnetic meridian. The vertical component of earth magnetic field is 0.25G. When train runs on the rails at speed 60 km/hr then the induced potential difference blw ends of its axle is

Q. Dip angle increases from ${30}^{\circ }$ to ${60}^{\circ }$ at a place if vertical plane in which needle is suspended is rotated by angle $\alpha$ from magnetic meridian. Then $\alpha$ is.

1. $\alpha ={45}^{\circ }$
2. $\alpha ={30}^{\circ }$
3. $\alpha =co{s}^{-1}\left(\frac{2}{3}\right)$
4. $\alpha =co{s}^{-1}\left(\frac{1}{3}\right)$