Physics Questions Answers
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57. If no external force acts on a system of bodies, the total linear momentum of the system of bodies remains constant. Which law states this ?
- Newton first law
- Newton second law
- Newton third law
- Principle of conservation of linear momentum
Answer :
Option D
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58. Light year is a unit of
- Time
- Light
- Distance
- Intensity of light
Answer :
Option C
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59. The incident ray, reflected ray and normal to the reflecting surface at the incident point all never lie in same plane.
- True
- False
Answer :
Option B
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60. Which instrument is used to determine the intensity of colours ?
- Cathetometer
- Chronometer
- Colorimeter
- Commutator
Answer :
Option C
Explanation:
Cathetometer - is used to determine heights,
Chronometer - is used to longitude of a vessel at sea,
Commutator - is used to convert AC to DC.
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61. What is unit of Viscosity ?
- coulomb
- newton second per square meter
- watt per meter per degree celcius
- joule per kilogram per Kelvin
Answer :
Option B
Explanation:
coulomb is unit of Electric Charge,
watt per meter per degree celcius is unit of Thermal Conductivity,
joule per kilogram per Kelvin is unit of Specific Heat capacity.
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62. Which of following in not a property of cathode ray.
- Cathode rays are invisible and travel in a straight line.
- These rays can ionise gases.
- These rays can penetrate through thin metal foils.
- These rays make materials cool on which they fall.
Answer :
Option D
Explanation:
These rays heat the materials on which they fall.
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63. All planets move around the sun in elliptical orbits, with the sun being at rest at one focus of the orbit.
- True
- False
Answer :
Option A