Physics MCQs
Physics Objective (Multiple Choice) General Knowledge & General Science Questions & Answers for SSC-CGL, UPPSC, NDA, CDS and all one day examinations of India.
1. What is the mean value of g at earth’s surface?
[A] 0.98 meter per second
[B] 9.8 meter per second
[C] 9.8 meter per second square
[D] 0.98 meter per second square
Show Answer
Correct Answer: C [9.8 meter per second square]
Notes:
The mean value of the acceleration due to gravity (often denoted as “g”) at Earth’s surface is approximately 9.81 meters per second squared (m/s²). This value represents the average gravitational acceleration experienced by objects on the surface of the Earth. It is important to note that this value is not constant everywhere on Earth’s surface and can vary slightly due to factors such as location, altitude, and the density of the Earth’s crust.
2. Which among the following character of mercury makes it suitable to use in barometers instead of water?
[A] Low density and low vapor pressure
[B] High density and high vapor pressure
[C] Low density and good conductor of heat
[D] High density and low vapor pressure
Show Answer
Correct Answer: D [High density and low vapor pressure]
Notes:
Mercury is typically used in barometers because it is denser and more viscous than water, which makes it more effective at measuring changes in atmospheric pressure. It also has High density and low vapor pressure than water. When atmospheric pressure changes, the mercury in the barometer will either rise or fall in the tube, allowing the barometer to accurately measure the pressure. Additionally, mercury has a lower freezing point and a higher boiling point than water, which makes it less likely to freeze or boil at normal temperatures and therefore more reliable for use in a barometer.
3. Which among the following temperature scale is based upon absolute zero?
[A] Celsius
[B] Fahrenheit
[C] Kelvin
[D] Rankine
Show Answer
Correct Answer: C [Kelvin]
Notes:
Kelvin is the base unit of temperature (SI unit), having the unit symbol K. The Kelvin temperature scale has an absolute zero (0°K) below which temperatures do not exist. It is the lowest possible temperature. At this temperature there is no motion and no heat. It is equivalent to 0°K, or -273.15° C, or at -460° F.
4. “Fermi” is a unit of which among the following?
[A] Mass
[B] Length
[C] Velocity
[D] Frequency
Show Answer
Correct Answer: B [Length]
Notes:
“Fermi” is the unit of length. The femtometre is an SI unit of length equal to 10⁻¹⁵ metres, which means a quadrillionth of one.
5. Which among the following property of the matter is studied in “Rheology”?
[A] Gravitation
[B] Viscosity
[C] Magnetic Properties
[D] Entropy
Show Answer
Correct Answer: B [Viscosity]
Notes:
Rheology is the study of the flow of matter, primarily in a liquid or gas state. It is related to Viscosity. In the science of rheology, a fluid’s changes are measured when there are actual forces (mechanical shear or pump pressure) induced.
6. For any object on the surface of earth, which among the following properties will be directly proportional to each other?
[A] It’s acceleration and it’s mass
[B] It’s mass and it’s weight
[C] It’s weight and it’s acceleration
[D] It’s speed and it’s velocity
Show Answer
Correct Answer: B [ It’s mass and it’s weight]
Notes:
The weight of an object and its mass are directly proportional. For a given gravitational field strength, the greater the mass of the object, the greater its weight.
7. A pressure cooker on a stove with its lid tightly closed and the whistle in position is an example of:
[A] open system
[B] closed system
[C] isolated system
[D] adiabatic system
Show Answer
Correct Answer: B [ closed system]
Notes:
A pressure cooker on a stove with its lid tightly closed and the whistle in position is an example of a closed-system thermodynamic process. In a closed-system thermodynamic process, the container (in this case, the pressure cooker) is sealed, and there is no exchange of matter with the surroundings. The pressure cooker is designed to be airtight, so no air or steam can escape while it’s cooking. This sealed environment allows for the buildup of pressure and temperature inside the cooker, which, in turn, speeds up the cooking process.
8. Who among the following is credited for the discovery of ‘Expanding Universe’?
[A] Edwin Hubble
[B] Niels Bohr
[C] S Chandra Shekhar
[D] C.V Raman
Show Answer
Correct Answer: A [Edwin Hubble]
Notes:
Edwin Hubble, an american astronomer, and was the first to prove that the universe is expanding. According to Expanding Universe theory, the universe is presently expanding. Hubble proved that there is a direct relationship between the speeds of distant galaxies and their distances from Earth. This is now known as Hubble’s Law.
9. What is the S.I unit of Pressure Energy?
[A] Nm
[B] Watt
[C] Joule
[D] No units
Show Answer
Correct Answer: C [ Joule ]
Notes:
Joule is the unit of Pressure energy. Pressure energy is the energy stored in a fluid due to the force per unit area applied onto it Pressure energy = Pressure x volume Its dimensional formula is M L2 T-2
10. What is the slope of the velocity-time graph when an object moves with constant negative acceleration, having positive initial velocity?
[A] 90°
[B] more than 90°
[C] less than 90°
[D] 0°
Show Answer
Correct Answer: B [more than 90°]
Notes:
When an object moves with constant negative acceleration, having positive initial velocity, the velocity-time graph is a straight line having slope more than 90°. When an object moves with constant positive acceleration, having positive initial velocity, the velocity-time graph is a straight line having slope less than 90°.