Physics GK Mock Test – 10

14 questions on “Physics GK Mock Test” objective questions series.

This article is important for anyone who is preparing for civil services, Bank PO exam or other government exams as such questions have been asked in all these exams in general studies or general knowledge section.

Question Section:

Que (226): Which colour of heat radiation represents the highest temperature?
A. Red
B. Black
C. White
D. Blue

Ans: White,
Objects radiate distinct colors of heat based on their temperature. The uppermost temperatures, like those existing in stars, can result in hues of white or even blue-white. In contrast, lower temperatures prompt objects to emit heat radiation appearing in red tones.

Que (227): Why are Clear nights colder than cloudy nights?
A. Because of absence of heat
B. Because of radiation
C. Because of more wind
D. none of these

Ans: Because of Radiation,
During clear nights, the Earth’s surface undergoes cooling through radiative processes. It emits infrared radiation into the cooler atmosphere, which subsequently dissipates into space. This progressive cooling persists through the night, leading to a reduction in surface temperature. Conversely, clouds function as insulating layers, capturing a portion of the heat that emanates from the Earth’s surface.

Que (228): Which does not wet the walls of the glass vessel in which it is kept?
A. Mercury
B. Copper
C. Sliver
D. Ethene

Ans: Mercury,
Mercury, a liquid metal, exhibits notable cohesive forces among its molecules, while its adhesive forces with glass are comparatively weak. This specific amalgamation of characteristics results in mercury adopting nearly spherical droplet formations, which refrain from spreading across or wetting the glass surface.

Que (229): If a proton of mass m is moving with the velocity of light, what will its mass be?
A. Once
B. Twice
C. Triple
D. Infinite

Ans: Infinite,
According to Einstein’s theory of relativity, as an object’s velocity approaches the speed of light, its relativistic mass increases.

Que (230): What is the best conductor of electricity?
A. Metals
B. Salt water
C. Cotton
D. Wood

Ans: Salt water,
Saltwater exhibits effective electrical conductivity due to the presence of charged entities known as ions. Upon dissolution, common table salt (sodium chloride, NaCl) undergoes dissociation, resulting in the creation of sodium ions (Na+) and chloride ions (Cl-). These ions possess the ability to move unrestricted within the solution, facilitating the transportation of electric charges.

Que (231): Which is the example of ideal black body?
A. A drain
B. A pin hole box
C. End of a tunnel
D. Newspaper tube end

Ans: A pin hole box.

Que (232): What is a graph is plotted taking °C along the Y-axis and of K along the X-axis?
A. Straight line
B. Vertical line
C. Increasing upwards
D. Decreasing downwards

Ans: Straight line,
K = °C+273.15.
So, absolute zero on the Kelvin scale is 0 K, which is equivalent to -273.15°C. Hence, if we plot this then we will get a straight line.

Que (233): Which laser type is used in a laser printer?
A. Laser beam
B. Selenium coated
C. Dye laser
D. Semicondutor laser

Ans: Semiconductor laser,
Semiconductor laser diodes, to produce the laser beam that forms the image on the photoreceptor drum or belt.

Que (234): How much is one barrel of oil approximately equal to?
A. 159 litres
B. 154 litres
C. 155 litres
D. 152 litres

Ans: ~159 litres.

Que (235): What is the energy of the winds and the waves?
A. Potential
B. Kinetic
C. Electric
D. Electromagnetic

Ans: Kinetic energy.
Kinetic energy is the energy an object possesses due to its motion.

Que (236): If the mass of the pendulum is doubled, what will happen to its time period?
A. Increases
B. Decreases
C. Remains same
D. No change

Ans: Remains same,
The time period of pendulum depends on length of the pendulum and gravity, hence by changing its mass the time period remains the same.
T=2π(L/g)*1/2
So, time period is directly proportional to the length of the pendulum and inversely proportional to the gravity.​​

Que (237): Wireless communication is reflected back to the earth’s surface by the which zone?
A. Atmosphere
B. Ionosphere
C. Stratosphere
D. none of these

Ans: Ionosphere,
Ionosphere has F2 layer between 200-500 km above earth’s surface, it has the ability to refract and reflect radio waves. Radio waves that reach the F2 layer can be refracted, or bent, back towards the Earth’s surface due to changes in ion density and composition in the ionosphere.

Que (238): Which are waves moving from a sitar to a listener in air?
A. Latitudinal progressive
B. Longitudinal progressive
C. Meridional progressive
D. none of these

Ans: Longitudinal progressive,
Longitudinal waves are identified by their oscillations occurring parallel to the direction of wave propagation. This motion gives rise to regions of compression and rarefaction as the waves travel through a medium.

Que (239): By whom are the planets are kept in motion in their respective orbits?
A. Gravitation and centrifugal force
B. Gravitation
C. Centrifugal force
D. Centripetal force

Ans: Gravitation and centrifugal force.

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