A compass needle whose magnetic moment is $60 \,amp × m^2$ pointing geographical north at a certain place, where the horizontal component of earth's magnetic field is $40\, \mu Wb/m^2$, experiences a torque $1.2 \times {10^{ - 3}}\,N \times m.$ What is the declination at this place......$^o$
$30$
$45$
$60$
$25$
A compass needle which is allowed to move in a horizontal plane is taken to a geomagnetic pole. It
Dip angle are $30^o$ and $45^o$ at two different places, then ratio of horizontal component of earth magnetic field at these place will be
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 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.....$^o$
The relations amongst the three elements elements earth's magnettic fleld, namely horizontal component $H$, vertical component $V$ and dip $\delta$ are, $( B_{E}=$ total magnetic fleld)