Ray Optics — Physics STD 12 Science — Question

C and Si both have the same lattice structure, having 4 bonding electrons in each. However, C is an insulator whereas Si is an intrinsic semiconductor. This is because
A. In case of C the valence band is not completely filled at absolute zero temperature.
B. In case of C the conduction band is partly filled even at absolute zero temperature.
C. The four bonding electrons in the case of C lie in the second orbit, whereas in the case of Si they lie in the third.
D. The four bonding electrons in the case of C lie in the third orbit, whereas for Si they lie in the fourth orbit.

The SI unit of magnetic flux is:

A very long bar magnet is placed with its north pole coinciding with the centre of a circular loop carrying as electric current i. The magnetic field due to the magnet at a point on the periphery of the wire is B. The radius of the loop is a. The force on the wire is:

Consider an electromagnetic wave propagating in vacuum. Choose the correct statement:

In positive logic, the logic state 1 corresponds to:

Which of the following electromagnetic waves is used in medicine to destroy cancer cells?

The optical path of a monochromatic light is same if it goes through 4.0 cm of glass or 4.5 cm of water.  If the refractive index of glass is 1.53, the refractive index of the water is(a) 1.30 (b) 1.36(c) 1.42(d) 1.46