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What is the correct ascending order for frequencies of the following radiations ?
1. Visible          2. X-rays
3. Ultraviolet     4. Radio waves

(a) 1, 3, 2, 4

(b) 3, 2, 4, 1

(c) 4, 1, 3, 2

(d) 4, 3, 1, 2
Nuclear fission is caused by the impact of :

(a) proton

(b) electron

(c) neutron

(d) none of these
Which of the following is used as a coolant in nuclear reactors ?

(a) Heavy water

(b) Cadmium

(c) Liquid sodium

(d) Graphite
Which of the following is good nuclear fuel ?

(a) Uranium-238

(b) Neptunium-239

(c) Thorium-236

(d) Plutonium-239
What is the wavelength of visible spectrum ?

(a) 1300-3000 Å

(b) 3900-7600 Å

(c) 7800-8000 Å

(d) 8500-9800 Å
In an atomic explosion, enormous energy is released which is due to the :

(a) conversion of neutrons into protons

(b) conversion of chemical energy into heat energy

(c) conversion of chemical energy into nuclear energy

(d) conversion of mass into energy
Which of the following statements are correctly associated with ultrasonic waves?
1. These are the acoustic waves of frequencies more than 20,000 Hertz.
2. When possible to use, these waves are preferred over X-rays for getting an image of internal organs because they are not harmful.
3. Their velocity is more than the velocity of sound.

(a) 1 only

(b) 1 and 2

(c) 2 and 3

(d) 1 and 3
Which of the following has the least penetrating power ?

(a) Alpha particles

(b) Beta particles

(c) Gamma rays

(d) All have the same penetrating power
Optic fibres are mainly used for which of the following ?

(a) Communication

(b) Weaving

(c) Musical instruments

(d) Food industry
Which of the following are most penetrating?

(a) α-rays

(b) β-rays

(c) γ-rays

(d) X-rays

38. Science for NDA / CDS / AFCAT

38. Science for NDA / CDS / AFCAT