CBSE
Multiple Choice QuestionsIn the given figure, what is the magnetic field induction at point O.
A uniform electric field and a uniform magnetic field acting along the same direction in a certain region. If an electron is projected along the direction of the fields with a certain velocity, then
It will turn towards the left of the direction of motion.
It will turn towards the right of the direction of motion
Its velocity will increase
Its velocity will decrease
A 250-Turn rectangular coil of length 2.1 cm and width 1.25 cm carries a current of 85 μA and subjected to a magnetic field of strength 0.85 T. Work done for rotating the coil by 180° against the torque is
9.1 μJ
4.55 μJ
2.3 μJ
2.3 μJ
Figure shows a circuit contains three identical resistors with resistance R = 9.0 Ω each, two identical inductors with inductance L = 2.0 mH each, and an ideal battery with emf ε= 18 V. The current'i' through the battery just after the switch closed is
2 mA
0 mA
2 A
2 A
Two identical bar magnets are fixed with their centres at a distance d apart. A stationary charge Q is placed at P in between the gap of the two magnets at a distance D from the centre O as shown in the figure.
The force on the charge Q is
zero
directed along OP
directed along PO
directed along PO
The magnetic moment of a diamagnetic atom is
much greater than one
one
equal to zero
equal to zero
A thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence the rod gains gravitational potential energy. The work required to do this comes from
The current source
The magnetic field
The induced electric field due to the changing magnetic field
The lattice structure of the material of the rod
Curie temperature is the temperature above which
ferromagnetic material becomes paramagnetic material
paramagnetic material becomes diamagnetic material
paramagnetic material becomes ferromagnetic material
paramagnetic material becomes ferromagnetic material
Above Curie temperature
a ferromagnetic substance becomes paramagnetic
a paramagnetic substance becomes diamagnetic
a diamagnetic substance becomes paramagnetic
a diamagnetic substance becomes paramagnetic
A rectangular, a square a circular and an elliptical loop, all in the (x-y) plane, are moving out of a uniform magnetic field with a constant velocity,
The magnetic field is directed along the negative z- axis direction. The induced emf, during the passage of these loops, out the field region, will not remain constant for
the rectangular, circular and elliptical loops
the circular and the elliptical loops
only the elliptical loops
only the elliptical loops
