The earth's magnetic field was flipped by $180^{\circ}$ a million years ago. This flip was relatively rapid and took $10^5 \,yrs$. Then, the average change in orientation per year during the flip was closest to ............ $s$

Which of the following relation is correct in magnetism

Angle of dip at a place is $30^o,$ and the horizontal component of earth's field is $5 \times 10^{-5}$ $tesla$, then the vertical component and the total magnetic field at that place is :-

Choose the correct option:

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

The magnetic needle of a tangent galvanometer is deflected at an angle $30^o$ due to a magnet. The horizontal component of the earth's magnetic field is $0.34 \times 10^{-4}\,T$ which is along the plane of the coil. The magnetic field due to magnet is