Of the following Fig., the lines of magnetic induction due to a magnet $SN$, are given by
$1$
$2$
$3$
$4$
The effective length of a magnet is $ 31.4 \,cm $ and its pole strength is $0.5\, Am$. The magnetic moment, if it is bent in the form of a semicircle will be.....$A{m^2}$
Force between two unit pole strength placed at a distance of one metre is
In two separate experiments the neutral points due to two small magnets are at a distance of $r$ and $ 2r$ n broad side-on position. The ratio of their magnetic moments will be
If a piece of metal was thought to be magnet, which one of the following observations would offer conclusive evidence
A small bar magnet has a magnetic moment $1.2 \,A-m^2$. The magnetic field at a distance $ 0.1\, m $ on its axis will be : ($\mu_0 = 4\pi \times 10^{-7} \,T-m/A$)