Prelims

Soft drinks such as colas contain significant quantities of

Which one of the following materials is very hard and very ductile ?

Most of the explosions in mines occur due to the mixing of

The stones formed in human kidney consist mostly of

Assertion (A) : Small glass beads fixed on traffic signals glow brightly when light falls upon them. Reason (R) : Light is totally reflected when the angle of incidence exceeds a certain critical value and light travelling in a denser medium is reflected from a rarer medium.

Assertion (A) : A man standing on a completely frictionless surface can propel himself by whistling. Reason (R) : If no external force acts on a system, its momentum cannot change.

Assertion (A) : In a motion picture, usually 24 frames are projected every second over the whole length of the film. Reason (R) : An image formed on the retina of eye persists for about 0.1 s after the removal of stimulus.

When a CD (Compact Disc used in audio and video systems) is seen in sunlight, rainbow like colours are seen. This can be explained on the basis of the phenomenon of

For reproducing sound, a CD (Compact Disc) audio player uses a

The memory of a computer is commonly expressed in terms of Kilobytes or Megabytes. A byte is made up of