Physics Objective (Multiple Choice) General Knowledge & General Science Questions & Answers for SSC-CGL, UPPSC, NDA, CDS and all one day examinations of India. These questions are part of GKToday’s 35000+ MCQs Bank Course in GKToday Android App
1. Which among the following can be measured with Anemometer?
[A] Water Velocity
[B] Wind Velocity
[C] Relative Humidity
[D] Absolute Humidity
Show Answer
Correct Answer: B [Wind Velocity]
Notes:
An anemometer is a device which used for measuring wind speed and direction. The term is derived from the Greek word anemos, which means wind, and it is used to describe any wind speed instrument used in meteorology.
2. When a tubelight breaks, a cracking sound is produced because ____?
[A] Pressure inside the lamp is less than atmospheric pressure
[B] Pressure inside the lamp is more than atmospheric pressure
[C] The lamp is filled with reactive gases
[D] The lamp is filled with mercury vapour
Show Answer
Correct Answer: A [Pressure inside the lamp is less than atmospheric pressure ]
Notes:
A fluorescent lamp tube is filled with a gas containing low pressure mercury vapor and argon, xenon, neon, or krypton. The pressure inside the lamp is around 0.3% of atmospheric pressure.
3. Which among the following defines cohesive force?
[A] the force of attraction acting between the molecules of same material
[B] the force of attraction acting between the molecules of different material
[C] the force of attraction acting between the atoms of same material
[D] None of the above
Show Answer
Correct Answer: A [the force of attraction acting between the molecules of same material]
Notes:
The force of attraction acting between the molecules of same material is known as cohesive force. Cohesive force is the action or property of like molecules sticking together, being mutually attractive.
4. What is the normal temperature of human being on Kelvin scale?
[A] 290
[B] 300
[C] 310
[D] 320
Show Answer
Correct Answer: C [310]
Notes:
The normal temperature for a human body is 310 kelvins is 36.85 degrees Celsius. The average normal body temperature is generally accepted as 98.6°F.
5. Which among the following planet / body shows anti-green house effect?
[A] Mars
[B] Venus
[C] Jupiter
[D] Titan
Show Answer
Correct Answer: D [Titan]
Notes:
In our solar System, Mars and Venus show the Green House Effect, but Titan, the largest planet of Saturn and Pluto, shows the opposite phenomena which is called Anti-Green House Effect.
6. Crystals of which of the following naturally-occuring substance exhibits both ‘pyroelectric’ and ‘piezoelectric’ properties making it versatile for application in the field of electronics?
[A] Quartz
[B] Mica
[C] Topaz
[D] grapite
Show Answer
Correct Answer: A [Quartz]
Notes:
Quartz crystals have piezoelectric properties: they develop an electric potential upon the application of mechanical stress. An early use of this property of quartz crystals was in phonograph pickups. A common piezoelectric use of quartz today is as a crystal oscillator. The quartz clock is a familiar device using the mineral. Quartz is also strongly pyroelectric. Temperature changes create positive and negative charges within the crystal.
7. Which of the following makes a CD or DVD show rainbow pattern?
[A] Diffraction of the Light
[B] Thin-Film Interference of the light
[C] Scattering of the light
[D] Polarisation of the light
Show Answer
Correct Answer: A [ Diffraction of the Light]
Notes:
A CD or DVD has closely spaced tracks which work as a diffraction grating to form the familiar rainbow pattern seen when looking at a disk.
8. By how many times are the Electrostatic forces stronger than the Gravitational Forces for a fixed distance?
[A] 102
[B] 1036
[C] 1012
[D] 2
Show Answer
Correct Answer: B [1036]
Notes:
Electrostatic forces are 1036 times stronger than the Gravitational Forces for a fixed distance. Electrostatic forces may be attractive or repulsive depending upon the charges. Electrostatic forces are conservative forces and obey inverse square law.
9. Which of the following is NOT a unit for measuring pressure?
[A] bar
[B] torr
[C] Pascal
[D] shake
Show Answer
Correct Answer: D [ shake ]
Notes:
bar, torr and Pascal are the units used for measuring pressure whereas shake is a unit of time. 1 bar = 105 Pa 1 bar = 760 torr 1 bar = 1 atmospheric pressure Shake is the smallest practical unit of time. 1 shake = 10-8s
10. Which of the following physical quantities has no units?
[A] Reynold Number
[B] Rydberg constant
[C] Wave number
[D] Hubble constant
Show Answer
Correct Answer: A [ Reynold Number ]
Notes:Reynold Number has no units. The Reynolds number is the ratio of inertial forces to viscous forces. It is used for predicting if a flow condition will be laminar or turbulent.
- Unit of Rydberg constant: m-1
- Unit of Wave number = m-1
- Unit of Hubble constant = sec-1
