Isogamous condition with non-flagellated gametes is found in:

$A$ current $i$ $A$ flows along an infinitely long straight thin-walled tube. The magnetic induction at any point inside the tube is:

The world's most problematic aquatic weed is:

$A$ magnetic needle lying parallel to a magnetic field is turned through $60^{\circ}$. The work done on it is $W$. The torque required to maintain the magnetic needle in the position mentioned above is

What is the role of limestone during the extraction of iron from haematite ore?

The equation of the circle passing through the point $(1, 2)$ and through the points of intersection of $x^2+y^2-4x-6y-21=0$ and $3x+4y+5=0$ is given by