41). 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 |
|
42). Nuclear fission is caused by the impact of :
| A). proton |
| B). electron |
| C). neutron |
| D). none of these |
|
43). Which of the following is used as a coolant in nuclear reactors?
| A). water |
| B). Cadmium |
| C). Liquid sodium |
| D). Graphite |
|
44). Which of the following is good nuclear fuel?
| A). Uranium-238 |
| B). Neptunium-239 |
| C). Thorium-236 |
| D). Plutonium-239 |
|
45). What is the wavelength of visible spectrum?
| A). 1300-3000 A |
| B). 3900-7600 A |
| C). 7800-8000 A |
| D). 8500-9800 A |
|
46). 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 |
|
47). 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 |
|
48). Which of the following has the least penetrating power?
| A). Alpha particles |
| B). Bata particles |
| C). Gamma particles |
| D). All have the same penetrating power |
|
49). Optic fibres are mainly used for which of the following?
| A). Communication |
| B). Weaving |
| C). Musical instruments |
| D). Food industry |
|
50). Which of the following are most penetrating?
| A). a-rays |
| B). b-rays |
| C). y-rays |
| D). X-rays |
|
