1. Hydrogen bomb is based upon the principle of ___________.
A. Nuclear fission
B. Nuclear fusion
C. Controller nuclear reaction
D. None of these
Ans: B The hydrogen bomb eventually relies upon atomic fusion (adding to the atomic nucleus) to release energy. Nuclear fusion is a nuclear reaction in which two or more atomic nuclei come very close and then collide at a very high speed and join to form a new type of atomic nucleus. During this process, matter is not conserved because some of the matter of the fusing nuclei is converted to photons
2. The south pole of the earth’s magnet is near the geographical _____________.
A. south
B. east
C. west
D. north
Ans: D The South Pole of the Earth’s magnet is in the geographical North because it attracts the North Pole of the suspended magnet and vice versa. Thus, there is a magnetic S-pole near the geographical North, and a magnetic N-pole near the geographical South
3. Number of basic SI unit is ___________.
A. 4
B. 7
C. 6
D. 5
Ans: B International System of Units (SI) is the modern metric system of measurement and the dominant system of international commerce and trade. It has seven base units.
4. The wire having a green plastic covering is a
A. Line wire
B. Neutral wire
A. Line wire
B. Neutral wire
C. Earth wire
D. None of these
Ans: C The earth wire is a crucial part of the home electrical system and is designed to protect against electric shock.
5. The working principle of a Washing Machine is ______________.
A. Centrifugation
B. Dialysis
C. Reverse osmosis
D. Diffusion
Ans: A Washing machine works on the principle of centrifugal force.
6. Sound and light waves both ______________.
A. have similar wavelength
B. obey the laws of reflection
C. travel as longitudinal waves
D. travel through vacuum
Ans: B The two laws of reflection of light are applicable to sound waves as well .The incident wave, the normal to the reflecting surface and the reflected wave at the point of incidence lie in the same plane. The angle of incidence is equal to the angle of reflection ∠r.
7. In an electric motor, the energy transformation is from _________________.
A. electrical to chemical
B. chemical to light
C. mechanical to electrical
D. electrical to mechanical
Ans: D An electric motor is an electrical machine that converts electrical energy into mechanical energy. The reverse of this would be the conversion of mechanical energy into electrical energy and is done by an electric generator.
8. The focal length of a plane mirror is __________________.
A. Positive
B. Negative
C. Zero
D. Infinity
Ans: C
D. Infinity
Ans: C
9. A dynamo converts _______________.
A. Mechanical energy into sound energy
B. Mechanical energy into electrical energy
C. Electrical energy into mechanical energy
D. None of these
Ans: B The dynamo, by attaching it in between the two tires, converts the mechanical energy (which of course, is produced by paddling) into electrical energy, and by connecting the wires going out of the dynamo to light, it glows without any flaw.
10. Which of the following is used in oven?
A. X-rays
B. UV-rays
C. Microwaves
D. Radio waves
Ans: C An oven is a thermally insulated chamber used for the heating, baking or drying of a substance and most commonly used for cooking.
11. Decibel is the unit of _______.
A. Speed of light
B. Intensity of sound
C. Intensity of heat
D. None of these
Ans: B Decibel (dB) unit is used for expressing the ratio between two amounts of electric or acoustic power for measuring the relative loudness of sounds.
12. The ozone layer in the atmosphere is at a height of about _____________.
A. 25 km
B. 50 km
C. 100 km
D. 200 km
Ans: B
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