# Physics GK Mock Test – 8

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 (176): In a p-type semiconductor, Which are the majority charge carriers?
A. Electrons
B. Protons
C. Free charge
D. Holes

Ans: Holes,

In a p-type semiconductor, the majority charge carriers are holes. Holes are created when certain impurities are introduced into the semiconductor material, resulting in vacant positions in the valence band of the crystal lattice. These impurities remove some valence electrons from the valence band, creating empty spaces where electrons should be.

Holes are considered positive charge carriers as they behave like positively charged particles. When an external electric field is applied to the semiconductor, the holes move in the opposite direction to the flow of electrons.

It’s important to note that holes are not actual physical particles but rather a conceptual representation of the missing electrons in the valence band.

Que (177): Which instrument used for measuring relative humidity in air?
A. Ammeter
B. Anemometer
C. Barometer
D. Hygrometer

Ans: Hygrograph,

The instrument used to measure relative humidity in the air is called a hygrometer. A hygrometer is specifically designed to determine the amount of water vapor present in the air relative to its maximum capacity at a given temperature. This device plays a crucial role in weather forecasting, indoor climate control, and various scientific and industrial applications. Hygrometers come in different types, such as mechanical hygrometers, electronic hygrometers, and psychrometers, each utilizing distinct principles to accurately measure humidity levels.

Que (178): What is the SI unit of Young’s modulus of elasticity?
A. Watt
B. Newton
C. Newton/m2
D. all of these

Ans: Newton/m2,

The SI unit of Young’s modulus of elasticity is pascals (Pa) or newtons per square meter. Young’s modulus is a fundamental material property that characterizes the stiffness or elasticity of a solid material. It defines the relationship between the stress (force per unit area) and strain (relative deformation) experienced by the material when subjected to tensile or compressive forces. Because both stress and strain have units of force per unit area, Young’s modulus is expressed in pascals (Pa), which is equivalent to newtons per square meter (N/m²) in the SI system. This unit quantifies the material’s resistance to deformation under applied stress.

Que (179): If temperature rises, what will be the coefficient of viscosity of liquid?
A. Increases
B. Decreases
C. Constant
D. no change

Ans: Decreases,

As a liquid’s temperature increases, the molecules within the liquid gain kinetic energy and move more freely, resulting in reduced internal friction and lower resistance to flow. Consequently, the liquid becomes less viscous.

Que (180): What is Electromagnetic radiation with maximum wavelength?
B. Microwaves
C. Visible light
D. X-rays

Que (181): What is the unit of luminous efficiency of an electric bulb?
A. nan
B. nan
C. nan
D. nan

Ans: Lumen / watt,

The unit of luminous efficiency of an electric bulb is expressed in lumens per watt (lm/W). Luminous efficiency is a measure of how effectively an electric bulb converts electrical power into visible light. A higher luminous efficiency value indicates that the bulb produces more light output (lumens) per unit of electrical power (watts), making it more energy-efficient and capable of providing brighter illumination with lower energy consumption.

Que (182): Which nuclear particles responsible for holding all nucleons together?
A. nan
B. nan
C. nan
D. nan

Ans: Mesons,

The nuclear particles responsible for holding all nucleons (protons and neutrons) together within the atomic nucleus are called “mesons.” Mesons are subatomic particles composed of one quark and one antiquark. They are a type of boson and play a significant role in mediating the strong nuclear force between protons and neutrons. This force is crucial for binding protons and neutrons together despite the electromagnetic repulsion between the positively charged protons. Mesons act as exchange particles, transmitting the strong force between nucleons and ensuring the stability and cohesion of the atomic nucleus.

Que (183): If one wants to throw a cricket ball to the maximum distance, then at which angle should he throw it ?
A. 44°
B. 45°
C. 46°
D. 47°

Ans: 45°.

Que (184): Rotation of the earth causes deflection of wind by which force?
A. Torque
B. Kinetic force
C. Coriolis force
D. Centripetal force

Ans: Coriolis force,

The Coriolis force is an apparent force that results from the Earth’s rotation and has a significant impact on the motion of objects, including air masses and winds.

Due to the Earth’s rotation, points on its surface move at varying speeds, with those closer to the equator moving faster than those nearer to the poles. This difference in linear speed causes moving air masses, known as winds, to experience a deflection to the right in the Northern Hemisphere and to the left in the Southern Hemisphere, relative to their original direction of motion. This phenomenon is referred to as the Coriolis effect.

Que (185): How are Air-pockets that cause aircrafts to lose altitude suddenly caused?
A. Temperature inversions
B. Increasing the humidity
C. Decreasing the humidity
D. Auto temperature

Ans: Temperature inversions.

Que (186): What is the escape velocity of a particle of mass m varies?

Ans: m^0 i.e. it remains constant,

The escape velocity is a constant value for a given astronomical body and depends solely on the mass and radius of that body. It is the minimum velocity required for an object to break free from the gravitational pull of the celestial body and move away indefinitely.

The escape velocity “v” can be calculated using the following formula:

v = (2GM/r)^0.5​​

Where:

• “G” is the gravitational constant (approximately 6.67430 × 10^-11 m^3 kg^-1 s^-2).
• “M” is the mass of the astronomical body (e.g., the Earth, the Moon, etc.).
• “r” is the distance from the center of the astronomical body to the particle.

Que (187): Foucault experiment is proof of which body?
A. Rotation of Earth
B. Rotation of moon around earth
C. Rotation of earth around the sun
D. All the planets rotate

Ans: Rotation of Earth,

The Foucault experiment serves as evidence of the Earth’s rotation. Conducted by the French physicist Léon Foucault in 1851, this experiment offered direct proof that the Earth rotates around its axis. Foucault suspended a large pendulum from a fixed point, and as the Earth rotated beneath the pendulum, the plane of its oscillation appeared to slowly rotate over time. The observed change in the pendulum’s direction of swing provided empirical support for the Earth’s rotation, bolstering the heliocentric model of the solar system.

Que (188): If the temperature of a patient is 40°C, what will be his temperature on Fahrenheit scale?
A. 104° F
B. 103° F
C. 102° F
D. 108° F

Ans: 104° F,

To convert a temperature difference from Celsius (°C) to Fahrenheit (°F), you can use the formula:

°F = (°C × 9/5) + 32

Given a temperature of 40°C, let’s convert it to Fahrenheit:

°F = (40 × 9/5) + 32 °F = (360/5) + 32 °F = 72 + 32 °F = 104 °F

So, a temperature difference of 25°C is equivalent to a temperature difference of 104°F.

Que (189): In which the radiant energy of the sun is transmitted?
A. Longitudinal wave
B. Transverse wave
C. Surface wave
D. Short wave

Ans: Short waves,

The sun’s radiant energy is mainly transmitted through short waves, commonly referred to as shortwave radiation or solar radiation. This type of radiation encompasses visible light, ultraviolet (UV) rays, and a portion of infrared radiation. As sunlight reaches the Earth’s atmosphere, a portion of the shortwave radiation is absorbed, while the remaining energy passes through to heat the Earth’s surface and drive essential natural processes such as photosynthesis.

Que (190): When can one record the lowest temperature of air?
A. Just before sunrise
B. Just after sunrise
C. Just before sunset
D. Just after sunset

Ans: Just before sunrise.

Que (191): Balloons are filled with which gas?
A. Helium
B. Neon
C. Xenon
D. Nitrogen

Ans: Helium,

Helium is commonly used to fill balloons because of its unique property of making them float. It is significantly lighter than air, which creates a buoyant force that enables helium-filled balloons to rise and stay aloft. When balloons are filled with helium, they become less dense than the surrounding air, causing them to ascend.

This property of helium makes it an ideal choice for various applications, including decorative purposes at parties, events, and celebrations.

Que (192): What happens when the water content in the atmosphere decreases?
A. It happens when temperature increases
B. It happens when temperature decreases
C. It happens when temperature is constant
D. none of these

Ans: It happens when temperature increases.

Que (193): What does the rusting of iron nail does to it?
A. Increases its weight
B. Decreases its weight
C. Weight stays constant
D. none of these

Ans: Increases its weight,

Rusting is a chemical process that takes place when iron or steel is exposed to oxygen and water or moisture. During this reaction, iron or steel combines with oxygen from the air and water to form a new compound called iron oxide, which is commonly known as rust. This process results in the formation of a substance that is heavier than the original iron or steel.

Que (194): Which are the The best and the poorest conductors of heat respectively?
A. Calcium (Ca), and lead (Pb)
B. Lead (Pb), and lithium (Li)
C. Silver (Ag), and potassium (K)
D. Silver (Ag), and glass

Ans: Silver (Ag), and glass.

Que (195): When light passes from air into glass it experiences change in which things?
A. Color
B. Speed
C. Velocity
D. A and B

Ans: Speed,

Light travels at different speeds in different mediums. In glass, the speed of light is slower than in air.

Que (196): Which types of light are strongly absorbed by plants?
A. Blue and white
B. Black and blue
C. Blue and red
D. Red and black

Ans: Blue and red,

Que (197): When two bodies stick together after the collision, what this is said?
A. Completely inelastic
B. Completely elastic
C. Completely semi elastic
D. none of these

Ans: Completely inelastic,

The two colliding objects lose some kinetic energy during the collision, and they stick together.

Que (198): A temperature of 25°C is equivalent to a temperature of how many F?
A. 45° F
B. 43° F
C. 49° F
D. 77° F

Ans: 77° F,

To convert a temperature difference from Celsius (°C) to Fahrenheit (°F), you can use the formula:

°F = (°C × 9/5) + 32

Given a temperature of 25°C, let’s convert it to Fahrenheit:

°F = (25 × 9/5) + 32 °F = (225/5) + 32 °F = 45 + 32 °F = 77

So, a temperature difference of 25°C is equivalent to a temperature difference of 77°F.

Que (199): What is the quantity that remains unchanged in a transformer?
A. Frequency
B. Speed
C. Velocity
D. All of these

Ans: Frequency,

Since the transformer itself does not generate or alter the frequency of the electrical power passing through it, the frequency remains constant throughout the transformer. It acts as a passive device that only transforms the voltage and current levels without affecting the frequency.

Que (200): Why is In a hydel station the motion produced in turbines?
A. Due to the flow of water
B. Due to the friction caused by water
C. Due to electricity
D. Due to hydroelectricity

Ans: Due to the flow of water,

In a hydroelectric power station, the motion is generated in turbines as a result of the force exerted by moving water. The underlying principle of hydropower generation involves the conversion of the kinetic energy present in flowing water into mechanical energy, which in turn drives the turbines.