A compass needle of oscillation magnetometer oscillates $20$ times per minute at a place $P$ of dip $30^{\circ}$. The number of oscillations per minute become $10$ at another place $Q$ of $60^{\circ} dip$. The ratio of the total magnetic field at the two places $\left(B_{Q}: B_{p}\right)$ is.

  • [JEE MAIN 2022]
  • A

    $\sqrt{3}: 4$

  • B

    $4: \sqrt{3}$

  • C

    $\sqrt{3}: 2$

  • D

    $2: \sqrt{3}$

Similar Questions

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 $18^o$. 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 $8 \times 10^{22}\; J\, T^{-1}$ 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?

The magnetic field of earth is due to

A dip needle vibrates in the vertical plane perpendicular to the magnetic meridian. The time period of vibration is found to be $2$ seconds. The same needle is then allowed to vibrate in the horizontal plane and the time period is again found to be $2$ seconds. Then the angle of dip is.....$^o$

At a place, the horizontal and vertical intensities of earth's magnetic field is $0.30$ Gauss and $0.173$  Gauss respectively. The angle of dip at this place is.....$^o$

Choose the correct option:

  • [JEE MAIN 2021]