Page 121 - Failure to Triumph - Journey of A Student

My Target Service Selection Board (SSB)

Q. What is SONAR?
Ans: SONAR stands for Sound navigation and ranging it is system that uses sound propagation to
navigate, communicate and detect objects on or under the surface of water. Ultrasonic waves are
transmitted through water. When these waves come in contact with any object then these are
reflected by the object in the water which produces an echo signal. By noting the time interval
between the generation of the pulse and reception of the echo-signal, the distance of the object can
be easily calculated.

Q. Difference between Sound Waves and Radio Waves.
Ans: 1. SONAR uses sound waves whereas the RADAR uses radio waves

2. Sound waves can be heard because of high frequency but we need electronic devices to hear or
see the radio waves.

3. Radio waves travel greater distance because of longer wavelength.
4. Sound waves cannot travel in vacuum because there is no air foe the waves to oscillate in.
Whereas the radio waves can travel through vacuum.

Q. What is AEWCS? What is the difference between AEWCS & AWACS?
Ans: AEWCS stands for Airborne Earning Warning and Control System. It is a system designed to
detect aircrafts, ships and vehicles at long ranges. AEWCS is used at high altitude; the radars on the
aircraft allow distinguishing between friendly and hostile objects hundreds of miles away. It carries
surveillance and performs command and control of air battle space by directing fighter and attack
aircrafts strikes. AEWCS and AWACS are the same. AWACS stands for Airborne Warning and
Control System.
Q. What is the Working Mechanism of a Gun?

Ans: Cartridges have the gun powder, projectile and a mechanism to ignite gunpowder packed into
one unit. When the gun’s trigger is pulled then it strikes the primer which catches fire which ignites
the gunpowder and the projectile is forced out of the shell because of expanding gases.
Q. What is the difference between Ballistic Missiles and Cruise Missiles?

Ans: Ballistic missiles are big, heavy and expensive. It has warheads on the rocket. Ballistic missiles
reach heights beyond the atmosphere and re-enter atmosphere & deliver warheads to predetermine
multiple targets. Its detection is easy.
Cruise missiles are small, light but less powerful. These missiles do not go in the atmosphere but
rather it stays very close to ground to prevent detection and hit the selected targets. Cruise missiles
are difficult to detect as compared to ballistic missiles.
Q. What is the difference between Carbine and Assault Rifle?

Ans: A rifle has a long barrel and has grooves inside the barrel which in result produces spin of a
bullet which counters the effect of wind. Rifles are heavy and are more accurate of long barrel length
and spin produced. Bullet shots from rifle travel faster.

Carbines have small barrel length without any grooves. These are lighter than assault rifles but these
are not so accurate and bullet shots travel slower than the rifle. The carbines are made from the
rifles.