25 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 (126): A small weight is put on the pressure cooker vent. It increases the pressure of the steam. Why?
A. The area of contact is under pressure
B. The area of of contact is suppressed
C. It does not make a difference
D. none of these

Ans: Area of contact is small,
A slight weight on the vent of the cooker serves to retain the steam within the cooker, leading to an increase in internal pressure. This buildup of pressure causes the boiling point of water to exceed 100℃.

Que (127): How can one can distinguish a telescope from a microscope?
A. By the length of the telescope
B. By the width of the telescope
C. By observing size of the lens
D. By observing size of the scenery

Ans: By observing size of the lens,
Telescopes:
Telescopes are primarily designed to observe distant and undefined objects, such as stars, planets, and galaxies. They excel at magnifying far-away celestial bodies and capturing light from astronomical events occurring in space.

Microscopes:
On the other hand, microscopes are employed to study small objects that are close-up but not yet discernible to the naked eye due to their minute size. These optical instruments are instrumental in examining microscopic structures, cells, microorganisms, and other tiny details that are not visible without magnification.

Que (128): Which sound is produced by a bat?
A. Sonic
B. Ultrasonic
C. Soft
D. Not hearable

Ans: Ultrasonic,
Bats produce ultrasonic waves as part of their echolocation process, which is a biological mechanism they use for navigation and hunting in the dark. When a bat emits ultrasonic waves, they are in the form of high-frequency sound waves that are beyond the range of human hearing (typically above 20 kHz).

Que (129): What is the distance of the nearest star besides the sun from the earth?
A. 4.4 light years
B. 4.7 light years
C. 4.9 light years
D. 4.2 light years

Ans: 4.2 light years,
It is about 4.22 light-years from Earth and is the closest star other than the sun. Alpha Centauri A and B orbit a common center of gravity every 80 years

Que (130): Which celestial body besides earth bear, The Sea of Tranquility’ and The Ocean of Storms’ ?
A. Moon
B. Sun
C. Saturn
D. Uranus

Ans: Moon,
The Sea of Tranquility” (Mare Tranquillitatis) is a large, dark, and flat plain on the Moon’s surface. It is located in the northern part of the Moon’s near side and gained historical significance as the landing site for Apollo 11, the first crewed mission to land on the Moon.

The Ocean of Storms” (Oceanus Procellarum) is another large dark plain on the Moon. It is located in the western part of the Moon’s near side and is the largest of the lunar “seas” or maria. Unlike “The Sea of Tranquility,” “The Ocean of Storms” is not associated with any specific Apollo landing missions.

Both “The Sea of Tranquility” and “The Ocean of Storms” are visible features on the lunar surface.

Que (131): Which explains that all the galaxies are receding?
A. Red Shift
B. Blue Shift
C. Green Shift
D. Orange Shift

Ans: Red shift,
When light from a distant object, such as a galaxy, travels through space and reaches us on Earth, its wavelength can be affected by the relative motion between the source and the observer. This effect is known as the Doppler effect.

If an object is moving away from us, the light it emits gets stretched, causing the wavelengths to become longer and shift toward the red end of the spectrum. This is known as redshift.

Que (132): Why does Short sightedness happens?
A. Due to elongation of eye balls
B. Due to elongation of pupils
C. Due to contrusion of eye balls
D. Due to contrusion of pupil

Ans: Due to elongation of eye balls,
Short-sightedness is often caused by the eyes growing slightly too long. This causes light to focus in front of the light-sensitive tissue (retina) at the back of the eye, leading to blurred vision when looking at distant objects.

Que (133): Why does the phenomenon of ‘trade winds’ takes place?
A. Due to convection of heat
B. Due to overheat
C. Due to humidity
D. none of these

Ans: Due to convection of heat,
Trade winds are primarily driven by the Earth’s rotation (Coriolis effect) and the differential heating of the Earth’s surface. Near the equator, the Sun’s rays strike the surface more directly, causing air to warm and rise. This creates a region of low pressure. As the warm air rises, cooler air from higher latitudes moves in to replace it, resulting in the trade winds.

Que (134): The quality of sound produced by an instrument depends on the which thing?
A. Number of overtones
B. Number of vibrations per second
C. Intensity of vibrations
D. Number of undertones

Ans: Number of overtones,

The specific combination and strength of overtones give different musical instruments their characteristic sound. Overtones are an essential aspect of musical instruments like strings, wind instruments, and percussion instruments.

In summary, overtones are the additional frequencies produced along with the fundamental frequency of a sound. They influence the timbre and character of the sound and are integral to the production of music and the unique sound of musical instruments.

Que (135): What is the order of magnitude of electric resistance of the human body (dry) ?
A. 10^6 ohm
B. 20^6 ohm
C. 30^6 ohm
D. 40^6 ohm

Ans: 10^6 ohm,
The human body’s resistance to electric current primarily comes from the skin, which acts as a barrier to the flow of electricity. Dry skin has higher resistance compared to wet skin, as moisture (sweat or water) can lower the skin’s resistance, making it more conductive.

Que (136): In electric supply lines in India, which parameter is kept constant?
A. Frequency
B. Power
C. Unit
D. Liquidity

Ans: Frequency,
Keeping the frequency constant ensures that all power generators in the grid are synchronized and operate in phase with each other. This synchronization prevents instability and disruptions in the grid.

Que (137): In an atomic nucleus, by which force are neutrons and protons held together?
A. Nuclear force
B. Static force
C. Magnetic force
D. None of these

Ans: Nuclear force,

This strong force is responsible for binding protons and neutrons together to form the nucleus of an atom. It is a short-range force that acts only over very small distances, typically within the range of a nucleus (on the order of femtometers or 10^(-15) meters).

Que (138): The wavelength of X-rays is of the order of how many angstrom?
A. 1 Angstrom
B. 20 Angstorm
C. 30 Angstorm
D. 40 Angstorm

Ans: 1 Angstrom,

The wavelength of X-rays is typically on the order of angstroms (Å). X-rays are a type of electromagnetic radiation with very short wavelengths, much shorter than visible light. The wavelengths of X-rays range from approximately 0.01 to 10 angstroms.

One angstrom is equal to 0.1 nanometers (nm) or 10^(-10) meters. X-rays have the ability to penetrate many materials and are widely used in various scientific, medical, and industrial applications, including X-ray imaging, crystallography, and material analysis, due to their short wavelengths and high energy.

Que (139): At the time of short-circuit, what will be the current in the circuit?
A. Increases heavily
B. Decreases heavily
C. Remains the same
D. None of these

Ans: Increases heavily,

A short circuit occurs when a low-resistance path is established directly between the positive and negative terminals of a power source, bypassing the normal load or load resistance.

High Current Flow: Since the resistance in a short circuit is significantly lower than the intended circuit components, a large amount of current flows through the short circuit. This can lead to excessive current and overheating of wires and electrical components.

Que (140): ‘Hydraulic brakes’ and ‘Hydraulic lift’ are devices, why are fluids used in them?
A. For transmitting pressure
B. For controlling the grip
C. For ease of the parts to work
D. None of these

Ans: For transmitting pressure,
The operation of the hydraulic lift is based on Pascal’s principle, which states that in a confined fluid at rest, any change in pressure applied at any point in the fluid is transmitted undiminished throughout the fluid in all directions.

Que (141): If a pendulum is allowed to oscillate into jar containing water, what will happen to it’s time period?
A. Increase
B. Decrease
C. Constant
D. Neutral

Ans: Increase,
When a pendulum is allowed to oscillate inside a jar filled with water, its speed will decrease due to the friction between the pendulum and the fluid.

Que (142): Which is the first large research reactor of India that uses U-233 as fuel?
A. DHRUVA
B. APSARA
C. KALPAKKAM
D. KAMINI

Ans: KAMINI

The first large research reactor in India that uses U-233 as fuel is the “KAMINI” reactor. KAMINI stands for “Kalpakkam Mini Reactor” and is located at the Indira Gandhi Centre for Atomic Research (IGCAR) in Kalpakkam, Tamil Nadu, India. It is a unique and significant research reactor in India, as it is one of the few reactors in the world that uses U-233 as fuel.

KAMINI is a 30 kWth (thermal power) research reactor that operates using U-233, which is obtained from the thorium-uranium fuel cycle.

Que (143): At a grid sub stations the voltage is stepped up to reduce loss of which thing?
A. Power
B. Frequency
C. Voltage
D. Resistance

Ans: Power.

Que (144): Instrument used to store the electric charge is known by which name?
A. Resistor
B. Diode
C. Capacitor
D. none of these

Ans: Capacitor,
A capacitor is a passive electronic component that can store electrical energy in the form of an electric field between two conductive plates separated by an insulating material called the dielectric. When a voltage is applied across the plates, an electric charge builds up on them, and the capacitor stores this charge.

Que (145): What happens to the level of mercury in the barometer tube when it is taken down in a coal mine?
A. It goes low
B. It rises
C. It stays constant
D. none of these

Ans: It rises
As we move down the Earth’s crust, the temperature increases. With minimal wind to distribute and moderate the warmth, the mercury in the barometer tube will rise.

Que (146): For which word, the letter ‘G’ has been used in ‘2G Spectrum’?
A. Gap
B. Generation
C. Gag

Ans: Generation,
G stands for generation for wireless technology and generation count increase when new technology come.

Que (147): What does Every object at a temperature above absolute zero does?
A. Freezes
B. Melts
C. Destroys

Every object at a temperature above absolute zero (OK) emits thermal radiation due to kinetic energy of molecules within the object.

Que (148): The value of which quantity remains same in all system of units?
A. Specific heat
B. Specific temperature
C. Specific gravity
D. Specific rate of friction

Ans: Specific gravity.

Que (149): A floating body always displaces liquid equal to its own ___________.
A. Weight
B. Mass
C. Quantity
D. Texture

Ans: Weight,
The “principle of flotation” states that when a boat or any floating object displaces a weight of water equal to its own weight, it will float. This principle means that a floating object displaces a fluid (such as water) with a weight equal to its own weight, allowing it to stay buoyant and remain afloat.

Que (150): When viewed in white light, why do soap bubbles show colours?
A. Because of interference
B. Because of Distortion
C. Because only white light is projected
D. none of these

Ans: Because of interference,
Soap bubbles show colors when viewed in white light due to a phenomenon called “thin-film interference.” When light passes through the thin film of the soap bubble, it undergoes multiple reflections and refractions at the two surfaces of the film (inner and outer surfaces). These reflections and refractions cause constructive and destructive interference of the light waves, resulting in the colors observed.