1
JEE Main 2021 (Online) 31st August Evening Shift
Numerical
+4
-1
A long solenoid with 1000 turns/m has a core material with relative permeability 500 and volume 103 cm3. If the core material is replaced by another material having relative permeability of 750 with same volume maintaining same current of 0.75 A in the solenoid, the fractional change in the magnetic moment of the core would be approximately $$\left( {{x \over {499}}} \right)$$. Find the value of x.
2
JEE Main 2021 (Online) 27th August Morning Shift
Numerical
+4
-1
A uniform conducting wire of length is 24a, and resistance R is wound up as a current carrying coil in the shape of an equilateral triangle of side 'a' and then in the form of a square of side 'a'. The coil is connected to a voltage source V0. The ratio of magnetic moment of the coils in case of equilateral triangle to that for square is 1 : $$\sqrt y$$ where y is ................. .
3
JEE Main 2021 (Online) 26th August Evening Shift
Numerical
+4
-1
A coil in the shape of an equilateral triangle of side 10 cm lies in a vertical plane between the pole pieces of permanent magnet producing a horizontal magnetic field 20 mT. The torque acting on the coil when a current of 0.2 A is passed through it and its plane becomes parallel to the magnetic field will be $$\sqrt x$$ $$\times$$ 10$$-$$5 Nm. The value of x is .................
4
JEE Main 2021 (Online) 26th August Morning Shift
Numerical
+4
-1
Two short magnetic dipoles m1 and m2 each having magnetic moment of 1 Am2 are placed at point O and P respectively. The distance between OP is 1 meter. The torque experienced by the magnetic dipole m2 due to the presence of m1 is ........... $$\times$$ 10$$-$$7 Nm.