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- Question
Radiocarbon is produced in the atmosphere as a result of
Options- A. collision between fast neutrons and nitrogen nuclei present in the atmosphere
- B. action of ultraviolet light from the sun on atmospheric oxygen
- C. action of solar radiations particularly cosmic rays on carbon dioxide present in the atmosphere
- D. lightning discharge in atmosphere
- Correct Answer
- collision between fast neutrons and nitrogen nuclei present in the atmosphere
- 1. A bucket of water is hung from a spring balance. A piece of iron is suspended in the water without touching the sides or touching the bottom of the the bucket. The reading of the spring balance
Options- A. will increase
- B. will decrease
- C. does not change
- D. varies with the increase of depth of the immersion of the iron piece Discuss
- 2. The velocity required to place a vehicle in orbit round the moon is _______ that required to place it in orbit round the earth
Options- A. less than
- B. Greater than
- C. equal to
- D. greater than or equal to Discuss
- 3. Electrical Energy is the energy of
Options- A. Protons
- B. Neutrons
- C. Electrons
- D. All the above Discuss
- 4. The value of acceleration due to gravity (g) at a distance of 2R from the surface of earth, where R is the radius of earth is ______.
Options- A. g/3
- B. g/4
- C. g/9
- D. g/2 Discuss
- 5. If ice floating on water in a vessel melts, the water level in the vessel _______.
Options- A. increases
- B. does not change
- C. first increases before decreasing
- D. decreases Discuss
- 6. Radian is used to measure
Options- A. Temperature
- B. Intensity of Flame
- C. Angle
- D. Solid Angle Discuss
- 7. When a bullet is fired from a gun
Options- A. the gun moves forward
- B. the gun jumps up
- C. the gun does not move
- D. the gun recoils with the same momentum as the bullet Discuss
- 8. For accurate scientific work, temperatures are often measured by
Options- A. mercury thermometers
- B. alcohol thermometers
- C. platinum resistance thermometers
- D. thermoelectric thermometers Discuss
- 9. Hot water is poured simultaneously in four metallic tumblers painted outside with different paints. After some time the water will be found to have cooled most in the tumbler painted.
Options- A. rough white
- B. rough black
- C. shining white
- D. shining black Discuss
- 10. Electrical Arcing occurs when Discuss
Physics problems
Search Results
Correct Answer: will increase
Explanation:
When the piece of iron is lowered into the water, the water level in the bucket increases. And so the pressure at the bottom of bucket also increases. Thus the total thrust at bottom also increases. Therefore the spring balance reading increases. Thus (a) is correct.
Correct Answer: less than
Explanation:
This orbital velocity at the moon is less because orbital velocity =
where 'r ' is the orbital radius. i.e the distance of the body from the center of the earth and 'g' is the acceleration due to gravity on the body in question. In the case of the moon, both r and g are less than in the case of the earth.
Correct Answer: Electrons
Explanation:
We know that Kinetic energy is the energy of a moving object and in the same way Electrical energy is the form of kinetic energy caused by moving electric charges called electrons.
Correct Answer: g/9
Correct Answer: does not change
Correct Answer: Angle
Explanation:
Kelvin is used to measure Temperature,
Candela is used to measure Intensity of flame,
Steredian is used to measure Solid Angle.
Correct Answer: the gun recoils with the same momentum as the bullet
Explanation:
Newton's III law involved
Correct Answer: platinum resistance thermometers
Explanation:
The resistance of metallic conductors e.g, platinum, increases with rise of temperature . The increase in temperature results in a decrease of current which can be recorded in a galvanometer if the conductor is included in an electrical circuit. Thus the temperature can be known; platinum resistance thermometer is used generally for accurate scientific work. When two dissimilar metals are joined at the ends, and these ends are subjected to a difference of temperature, a current flows through the metals. Greater the difference of temperature , greater the current. So the curent strength can form the basis for measuring the difference in temperature. And when one of these temperatures is known, we can calculate the other.
Correct Answer: rough black
Explanation:
Black surfaces are good emitters of heat. If the black surface is rough too, the emitting will be better. Shinning surfaces reflect black radiation . So if the black surface is also shining the effectiveness of emitting heat is lessened.
Correct Answer: An electric arc is a visible plasma discharge between two electrodes that is caused by electrical current ionizing gasses in the air Electric arcs occur in nature in the form of lightning
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