1.
Which of the following has no units?
Correct Answer
B. Tensile strainÂ
Explanation
Tensile strain is a dimensionless quantity that represents the change in length of an object divided by its original length. Since it is a ratio of lengths, it does not have any units. The other options, thermal capacity, acceleration, and impulse, all have units associated with them. Thermal capacity is measured in units of energy per degree Celsius, acceleration is measured in units of meters per second squared, and impulse is measured in units of Newton-seconds.
2.
Candela is the unit of …………………
Correct Answer
C. Luminous intensity Â
Explanation
Candela is the unit of luminous intensity. Luminous intensity refers to the amount of light emitted or reflected from a particular direction. It is a measure of the brightness of a light source as perceived by the human eye. The candela is defined as the luminous intensity in a given direction of a source that emits monochromatic radiation of frequency 540 terahertz and has a radiant intensity in that direction of 1/683 watt per steradian.
3.
Which of the following is not a physical quantity?
Correct Answer
C. Henry
Explanation
The question asks for a physical quantity that is not included in the given options. The options include "Candela," "Henry," and "Kelvin." Candela is the SI unit for luminous intensity, Henry is the SI unit for inductance, and Kelvin is the SI unit for temperature. Therefore, the correct answer is "Henry," as it is the only option that does not represent a physical quantity.
4.
Which one is not a dimension?
Correct Answer
D. Kelvin
Explanation
*##*Correct*##*Wrong
5.
Which of the following is NOT a method to reduce friction?
Correct Answer
C. Throwing sand on the Ground
Explanation
Throwing sand on the ground does not reduce friction; instead, it increases it. When sand is thrown on the ground, it creates roughness and increases the contact area between surfaces, leading to more friction. Lubrication, on the other hand, reduces friction by providing a layer between surfaces, reducing direct contact. Polishing also reduces friction by making surfaces smoother, reducing the roughness that causes friction. Therefore, throwing sand on the ground is not a method to reduce friction.
6.
Friction between moving parts of machine causes
Correct Answer
A. Heat
Explanation
Friction between moving parts of a machine causes heat. When two surfaces rub against each other, the friction generated converts mechanical energy into heat energy. This heat can cause the temperature of the machine to increase, which may lead to various consequences such as wear and tear, reduced efficiency, or even damage to the machine if not properly managed or lubricated.
7.
The force of friction depends on
Correct Answer
C. A & B
Explanation
The force of friction depends on the nature of the surface of contact and the materials of objects in contact. The nature of the surface of contact refers to whether it is rough or smooth, which affects the amount of friction. The materials of objects in contact also play a role, as different materials have different coefficients of friction. Therefore, both factors, the nature of the surface and the materials of objects, determine the force of friction.
8.
The body will move only when
Correct Answer
B. Force of friction < applied force
Explanation
The correct answer is "Force of friction < applied force." This means that the body will move only when the force of friction, which opposes the motion, is less than the applied force. In other words, if the force of friction is greater than the applied force, the body will not move.
9.
Different types of surfaces create different amount of friction
Correct Answer
A. True
Explanation
Friction is a force that opposes motion and it depends on the nature of the surfaces in contact. Different surfaces have different textures and properties, which can affect the amount of friction they generate. For example, rough surfaces tend to create more friction compared to smooth surfaces. Therefore, it is true that different types of surfaces create different amounts of friction.
10.
A sledge is pulled 10m by a force 40N.what is the work done?
Correct Answer
A. 400 Nm
Explanation
The work done is calculated by multiplying the force applied to an object by the distance it is moved. In this case, the force applied is 40N and the distance moved is 10m. Therefore, the work done is 40N x 10m = 400 Nm.
11.
Calculate the potential energy of Dam if the height is 200m and the mass of the water is 5kg (g=10m/s2)
Correct Answer
D. 10 KJ
Explanation
The potential energy of an object is given by the formula PE = mgh, where m is the mass, g is the acceleration due to gravity, and h is the height. In this case, the mass of the water is given as 5kg, the height is given as 200m, and the acceleration due to gravity is given as 10m/s^2. Plugging these values into the formula, we get PE = 5kg * 10m/s^2 * 200m = 10,000 J = 10 KJ. Therefore, the correct answer is 10 KJ.
12.
A girl whose mass is 40kg walks up a flight of 20 steps each 150mm height in 10secs.find the average power developed (g=10m/s2)
Correct Answer
C. 120 W
Explanation
The average power developed can be calculated by dividing the work done by the time taken. The work done can be calculated by multiplying the force exerted (which is equal to the girl's weight, given by mass x acceleration due to gravity) by the distance covered (which is equal to the height of each step multiplied by the number of steps). The time taken is given as 10 seconds. Therefore, the average power developed is 120 W.
13.
A body of mass 4kg moves through a distance 80m, calculate the work done on the body. (g=10m/s2)
Correct Answer
B. 3.2 KJ
Explanation
The work done on an object can be calculated using the formula W = F * d, where W is the work done, F is the force applied, and d is the distance over which the force is applied. In this case, the force applied can be calculated using the formula F = m * g, where m is the mass of the object and g is the acceleration due to gravity. Plugging in the given values, F = 4kg * 10m/s^2 = 40N. The work done is then calculated as W = 40N * 80m = 3200J, which is equal to 3.2 KJ.
14.
An engine raises 100kg of water through a height 60m in 20sec.what is the power of the engine. (g=10m/s2)
Correct Answer
B. 3 KW
Explanation
*##*Correct*##*Incorrect
15.
- If 2 resistors of 5kΩ and 7kΩ are connected in series across a 15V battery, then the current flowing through each of the resistance should be
Correct Answer
D. 1.25 mA
Explanation
*##*Correct*##*Incorrect
16.
- A car fuse marked 3A operates optimally on 12V battery. calculate the resistance of the fuse
Correct Answer
B. 4Ω
Explanation
*##*correct*##*incorrect
17.
The opposing capacity of materials against the current flow is
Correct Answer
C. Susceptance
Explanation
*##*Correct*##*Incorrect
18.
Which of the following factors does not affect the electrical resistance of a wire?
Correct Answer
B. Mass
Explanation
*##*Correct*##*Wrong
19.
An electrician wishes to cut a copper wire (ρ=1.724∗10−8Ωm) that has no more than 10Ω of resistance. The wire has a radius of 0.725mm. Approximately what length of wire has a resistance equal to the maximum 10Ω ?
Correct Answer
A. 960 M
Explanation
*##*Correct*##*Incorrect
20.
A rod 150cm long and of diameter 2cm is subjected to an axial pull of 20kN. What will be the stress?
Correct Answer
C. 63.6 N/mm2
Explanation
*##*Correct*##*Wrong
21.
The stress in a rod is 70 N/mm2 and the modulus of elasticity is 2 x 105 N/mm2. what will be the strain in the rod?
Correct Answer
C. 0.00030
Explanation
*##*Correct*##*Incorrect
22.
Which of the following material is more elastic?
Correct Answer
A. Rubber
Explanation
*##*Correct*##*Wrong
23.
The limit beyond which the material does not behave elastically is known as
Correct Answer
D. Yield point
Explanation
*##*correct*##*wrong
24.
The property of a material by which it can be beaten or rolled into thin sheets, is called
Correct Answer
D. Malleability
Explanation
*##*correct*##*wrong
25.
The dimension of density is __
Correct Answer
A. ML-3
Explanation
*##*correct*##*incorrect
26.
​​​​​​_________ is the instrument of measurement of atmospheric pressure
Correct Answer
C. Barometer
Explanation
*##*Correct*##*Incorrect
27.
MLT-2 is the dimension of ___
Correct Answer
C. Force
Explanation
*##*Correct*##*Incorrect
28.
The instrument of measurement of weight is _____
Correct Answer
B. Spring balance
Explanation
A spring balance is an instrument used to measure weight. It consists of a coiled spring that stretches when a weight is attached to it. The amount of stretch in the spring is directly proportional to the weight applied, allowing for an accurate measurement of weight. This makes the spring balance a commonly used tool in various industries and everyday life for measuring the weight of objects.
29.
Which of the following is a scalar quantity
Correct Answer
A. Time
Explanation
*##*Correct*##*Incorrect
30.
​​​​​A faulty thermometer registers 102.50C at 1000C. If the thermometer has no zero error, what will it register at 550C ?
Correct Answer
D. 56.4 oC
Explanation
The faulty thermometer registers a temperature that is 2.5 degrees higher than the actual temperature. Therefore, if the actual temperature is 55 degrees Celsius, the thermometer will register 55 + 2.5 = 57.5 degrees Celsius. However, since the thermometer has no zero error, we need to subtract the error at 0 degrees Celsius. Since the error is 2.5 degrees at 100 degrees Celsius, it will be 2.5 * (55/100) = 1.375 degrees at 55 degrees Celsius. Therefore, the thermometer will register 57.5 - 1.375 = 56.125 degrees Celsius, which is closest to 56.4 degrees Celsius.
31.
The ice and steam points on a mercury-in-glass thermometer are 10cm and 30cm respectively. Calculate the temperature in degree Celsius, when the mercury meniscus is at the 14cm mark
Correct Answer
A. 20 oC
Explanation
*##*Correct*##*Incorrect
32.
The pressure at the ice point for a constant-volume gas thermometer is 4.81 x 104 Pa while that at the steam point is 6.48 x 104 Pa. What pressure would this thermometer indicate at 500C?
Correct Answer
A. 5.645 x 100C
Explanation
*##*Correct*##*Incorrect
33.
A platinum-resistance thermometer has a resistance of 4ῼ at 00C and 12ῼ at 1000C. Assuming that the resistance changes uniformly with temperature, calculate the resistance of the thermometer when the temperature is 450C.
Correct Answer
A. 6.0 ῼ
Explanation
*##*Correct*##*Incorrect
34.
The readings on the pressure scale at the steam and ice points are 800mmHg and 300mmHg respectively. Determine the corresponding temperature in degree Celsius when it reads 450mmHg.
Correct Answer
B. 30
Explanation
The correct answer is 30. The pressure and temperature of a substance are directly proportional, according to Gay-Lussac's Law. Therefore, we can use the proportionality to find the corresponding temperature. The difference between the pressure at the steam point and the ice point is 800mmHg - 300mmHg = 500mmHg. The difference between the temperature at the steam point and the ice point is 100°C. Therefore, the temperature corresponding to a pressure of 450mmHg can be calculated using the proportion: (450mmHg - 300mmHg) / 500mmHg = (T - 30°C) / 100°C. Solving for T gives T = 30°C.
35.
​​​​​Which of the following is a not an application of surface tension
Correct Answer
D. Falling of a metal bob through water
Explanation
The falling of a metal bob through water is not an application of surface tension because surface tension is the force that causes the surface of a liquid to behave like a stretched elastic sheet. It is responsible for phenomena such as capillary action, where liquids can rise in narrow tubes against the force of gravity. However, the falling of a metal bob through water is simply an example of an object sinking due to its own weight and the buoyant force exerted by the water. Surface tension does not play a role in this scenario.
36.
Which of the following is not a way of reducing surface tension on water
Correct Answer
C. By adding sand
Explanation
Adding sand to water does not reduce surface tension. Surface tension is the force that causes the surface of a liquid to behave like a stretched elastic sheet. Adding soaps/detergents, heating the liquid, and adding kerosene all reduce surface tension. Soaps and detergents contain molecules that have a hydrophilic (water-attracting) and hydrophobic (water-repelling) end, which disrupts the cohesive forces between water molecules. Heating the liquid increases the kinetic energy of the molecules, weakening the intermolecular forces and reducing surface tension. Kerosene is a nonpolar substance that does not interact strongly with water, reducing surface tension. However, sand does not have any effect on surface tension as it does not interact with water molecules in a way that reduces the cohesive forces at the surface.
37.
​​​​​​The following processes are explained by surface tension except
Correct Answer
A. Water rising up a capillary tube
Explanation
Surface tension is the property of a liquid that allows it to resist external forces and minimize its surface area. It is responsible for phenomena such as the formation of droplets and the cohesion of liquid molecules. However, the process of water rising up a capillary tube is not explained by surface tension alone. This process is mainly due to capillary action, which is the result of adhesive and cohesive forces between the liquid and the walls of the tube.
38.
Which of the following is true of the meniscus of mercury in a capillary tube
Correct Answer
C. The meniscus is convex
Explanation
The meniscus of mercury in a capillary tube is convex. This means that the surface of the mercury is curved upwards at the edges, forming a rounded shape. This is due to the cohesive forces between the mercury molecules being stronger than the adhesive forces between the mercury and the glass of the capillary tube. As a result, the mercury forms a convex shape, with the highest point in the center of the meniscus.
39.
​​​​Which of the following statement is not true
Correct Answer
B. Mercury wets glass
Explanation
The statement "Mercury wets glass" is not true because mercury does not wet glass. Wetting is the ability of a liquid to spread out and make contact with a solid surface. Mercury does not wet glass because it forms droplets on the surface instead of spreading out.
40.
Which of the following statement is not correct
Correct Answer
B. Like charges repel
Explanation
Like charges repel because they have the same charge, either positive or negative. According to the principle of electrostatics, like charges will exert a force on each other that pushes them away. This is due to the electrostatic force, which is the force between two charged objects. When the charges are the same, the force is repulsive, causing the charges to repel each other. This phenomenon is observed in various situations, such as when two positively charged objects or two negatively charged objects are brought close to each other.
41.
Gold-leaf electroscope is used to
Correct Answer
A. Detect the presence of charges on a body
Explanation
The gold-leaf electroscope is a device used to detect the presence of charges on a body. When a charged object is brought close to the electroscope, the gold leaves repel each other due to the like charges. This indicates the presence of charges on the body. The greater the charge on the body, the greater the separation of the gold leaves. Therefore, the gold-leaf electroscope is commonly used in experiments and demonstrations to detect the presence of electric charges.
42.
When the pointed end of an uncharged optical pin is brought near the cap of a positively charged electroscope, it is observed that the gold leaves
Correct Answer
A. Collapse slowly
Explanation
When the pointed end of an uncharged optical pin is brought near the cap of a positively charged electroscope, the positive charges in the electroscope are attracted to the negative charges in the pin. This causes the positive charges in the electroscope to move closer to the pin, resulting in the collapse of the gold leaves. Since the pin is uncharged, there is no repulsion between the charges in the electroscope, which is why the collapse is slow rather than rapid.
43.
Two different materials rubbed against each other acquire opposite charges when separated. This is an example of charging by
Correct Answer
B. Friction
Explanation
When two different materials are rubbed against each other, the friction between them causes the transfer of electrons from one material to the other. This transfer of electrons results in one material acquiring a positive charge and the other material acquiring a negative charge. Therefore, the statement "Two different materials rubbed against each other acquire opposite charges when separated" is an example of charging by friction.
44.
A negatively charged rod is held close to an uncharged metal ball on an insulating stand. The ball will
Correct Answer
D. Have an excess of positive charges on the side nearest the rod
Explanation
When a negatively charged rod is held close to an uncharged metal ball, the negatively charged rod repels the electrons in the metal ball. As a result, the electrons are pushed away from the rod and towards the opposite side of the ball. This causes an excess of positive charges to accumulate on the side of the ball nearest to the rod, while the side farthest from the rod remains neutral. Therefore, the correct answer is "have an excess of positive charges on the side nearest the rod."
45.
Which of the following cannot be explained by the molecular theory of matter?
Correct Answer
A. Conduction
Explanation
Conduction is the transfer of heat through direct contact between particles. The molecular theory of matter explains that heat is transferred through the collision of particles. However, conduction cannot be explained solely by this theory because it also involves the movement of free electrons in conductive materials. Therefore, the molecular theory of matter cannot fully explain conduction.
46.
Highly polished silvery surface are
Correct Answer
A. Poor absorbers and poor emitters of radiation
Explanation
Highly polished silvery surfaces are poor absorbers and poor emitters of radiation because their smooth and reflective surfaces prevent them from absorbing and emitting radiation effectively. Instead, they reflect most of the radiation that comes into contact with them. This property makes them suitable for applications such as mirrors or reflective coatings, where their ability to reflect light is desired.
47.
Land breeze occurs
Correct Answer
D. As a result of heat transfer by convection
Explanation
Land breeze occurs as a result of heat transfer by convection. During the day, the land heats up faster than the water. This causes the air above the land to become warmer and rise, creating a low-pressure area. The cooler air over the water then moves towards the land to fill this void, resulting in a land breeze. Convection is the process of heat transfer through the movement of fluids or gases, and in this case, it explains how the warmer air rises and the cooler air moves in to replace it, causing the land breeze.
48.
In the formation of sea breeze, wind blows from
Correct Answer
D. Sea to land
Explanation
Sea breeze is a local wind that occurs during the day near coastal areas. It is caused by the temperature difference between the land and the sea. During the day, the land heats up faster than the sea, causing the air above the land to become warmer and rise. As a result, cooler air from the sea moves in to replace the rising warm air, creating a breeze that blows from the sea to the land. Therefore, the correct answer is "sea to land".
49.
Which of the following statements distinguishes thermal conduction from convection?
I. Conduction requires a material medium while convection does not
II. In convection, there is actual motion of hot materials, while in conduction, molecules vibrate faster about there mean positions
III. Conduction takes place in solids while convection takes place in fluids.
Correct Answer
A. I and II only
Explanation
Statement I is correct because thermal conduction requires a material medium, such as a solid or a liquid, for the transfer of heat. On the other hand, convection does not require a material medium as it involves the actual motion of hot materials, such as fluids, to transfer heat. Statement II is also correct because in conduction, heat is transferred through the vibration of molecules, which causes them to collide with neighboring molecules and transfer energy. In convection, however, there is actual motion of hot materials, such as fluids, which carry heat from one place to another. Statement III is incorrect because conduction can also take place in fluids, such as in the case of heat transfer through a metal rod immersed in a liquid.
50.
The magnitude of an expansion or contraction of a substance depends on the
I. temperature change II. Nature of the substance III. Size of the substance
Correct Answer
D. I, II and III
Explanation
The magnitude of an expansion or contraction of a substance depends on the temperature change, the nature of the substance, and the size of the substance. This means that all three factors play a role in determining the extent of expansion or contraction. Temperature change affects the kinetic energy of the particles, causing them to move faster or slower, leading to expansion or contraction. The nature of the substance determines its molecular structure and bonding, which affects its ability to expand or contract. The size of the substance determines the amount of material present, which can also impact the magnitude of expansion or contraction.