Magnetism And Matter — Physics STD 12 Science — Question

A magnet of magnetic moment M and pole strength m is divided in two equal parts, then magnetic moment of each part will be(a) M(b) M/2(c) M/4(d) 2M

The fundamental particles of the nucleus of an atom are :

Thermal neutrons are those which(a) Are at very high temperature(b) Move with high velocities(c) Have kinetic energies similar to those of surrounding molecules (d) Are at rest

Two insulated charged conducting spheres of radii 20 cm and 15 cm respectively and having an equal charge of 10 C  are connected by a copper wire and then they are separated. Then(a) Both the spheres will have the same charge of 10 C (b) Surface charge density on the 20 cm  sphere will be greater than that on the 15 cm  sphere(c) Surface charge density on the 15 cm sphere will be greater than that on the 20 cm  sphere(d) Surface charge density on the two spheres will be equal

If a coil made of conducting wires is rotated between poles pieces of the permanent magnet. The motion will generate a current and this device is called(a) An electric motor(b) An electric generator(c) An electromagnet (d) All of above

Which one of these is non-divisible(a) Nucleus(b) Photon(c) Proton(d) Atom

An electron is moving in the north direction. It experiences a force in vertically upward direction. The magnetic field at the position of the electron is in the direction of(a) East(b) West(c) North(d) South

A convex lens of focal length 25 cm and a concave lens of focal length 10 cm are joined together.  The power of the combination will be(a) – 16 D (b) + 16 D(c) – 6 D   (d) + 6 D

An astronomical telescope of ten fold angular magnification has a length of 44 cm. The focal length of the objective is