The lines joining the places of the same horizontal intensity are known as
Isogonic lines
Aclinic lines
Isoclinic lines
Isodynamic lines
Name the elements of the earth’s magnetic field.
Dip angle in vertical plane at an angle ${\cos ^{ - 1}}\,\left( {\frac{1}{{\sqrt 2 }}} \right)$ from magnetic meridian is $60^o$, then actual dip at that place
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 ............ $s$
A compass needle free to turn in a horizontal plane is placed at the centre of circular coil of $30$ turns and radius $12 \;cm .$ The coil is in a vertical plane making an angle of $45^{\circ}$ with the magnetic meridian. When the current in the coil is $0.35 \;A$, the needle points west to east.
$(a)$ Determine the horizontal component of the earth's magnetic field at the location.
$(b)$ The current in the coil is reversed, and the coil is rotated about its vertical axis by an angle of $90^{\circ}$ in the anticlockwise sense looking from above. Predict the direction of the needle. Take the magnetic declination at the places to be zero.
The angle of dip at a certain place on earth is $60^o$ and the magnitude of earth's horizontal component of magnetic field is $0.26\, G$. The magnetic field at the place on earth is.....$G$