Diploma 1st Semester Applied Physics MCQ with Answer & Explanation
Applied Physics MCQ Practice Set
Preparing for the WBSCTE Diploma 1st Semester Applied Chemistry examination? This post features a carefully selected collection of important Applied Chemistry MCQs with correct answers and easy-to-understand explanations, designed to help Diploma Engineering students prepare effectively for their semester exams.
Rather than relying only on memorization, these MCQs focus on developing a clear understanding of the fundamental concepts of Applied Chemistry. Practising these questions can help improve your conceptual knowledge, accuracy, and confidence while preparing for the examination.
This MCQ practice set is particularly useful for Diploma Engineering 1st Semester students who are preparing for their WBSCTE semester examination.
UNIT 1: Physical World, Units and Measurements
1
Which one of the followings is a derived unit?
(2025)
Correct Answer: B. cm/second
A derived unit is formed by mathematical combinations of fundamental units. cm/second represents speed, which is derived from length divided by time.
A derived unit is formed by mathematical combinations of fundamental units. cm/second represents speed, which is derived from length divided by time.
2
Which of the following quantity is dimensionless?
(2026)
Correct Answer: D. strain
Strain is the ratio of change in dimension to original dimension. Since both quantities have the same dimensions, the dimensions cancel out.
Strain is the ratio of change in dimension to original dimension. Since both quantities have the same dimensions, the dimensions cancel out.
3
The number of significant figures in 0.000502 is:
(2026)
Correct Answer: C. 3
Leading zeros are not significant. Therefore, the significant digits are 5, 0 and 2, giving 3 significant figures.
Leading zeros are not significant. Therefore, the significant digits are 5, 0 and 2, giving 3 significant figures.
4
If the percentage error in measurement of the radius of a sphere is 2%, then the percentage error in measurement of its volume is:
(2025, 2023)
Correct Answer: B. 6%
Volume of a sphere is V = (4/3)πr³.
Therefore, percentage error in volume = 3 × percentage error in radius = 3 × 2% = 6%.
Volume of a sphere is V = (4/3)πr³.
Therefore, percentage error in volume = 3 × percentage error in radius = 3 × 2% = 6%.
5
Which of the following pairs does not have the same dimensional formula?
(2024)
Correct Answer: C. Velocity and Angular velocity
Velocity has dimension [LT⁻¹], whereas angular velocity has dimension [T⁻¹]. Therefore, their dimensional formulas are different.
Velocity has dimension [LT⁻¹], whereas angular velocity has dimension [T⁻¹]. Therefore, their dimensional formulas are different.
6
The correct number of significant figures in 0.6230 is:
(2024)
Correct Answer: A. 4
The digits 6, 2, 3 and the trailing zero after the decimal point are significant. Therefore, there are 4 significant figures.
The digits 6, 2, 3 and the trailing zero after the decimal point are significant. Therefore, there are 4 significant figures.
7
Which of the following pairs of physical quantities does not have same dimensional formula?
(2023)
Correct Answer: C. tension and surface tension
Tension is a force with dimension [MLT⁻²], whereas surface tension is force per unit length with dimension [MT⁻²].
Tension is a force with dimension [MLT⁻²], whereas surface tension is force per unit length with dimension [MT⁻²].
8
The specific gravity of a substance is 2.5. The density of the substance in kg/m³ is:
(2023)
Correct Answer: C. 2.5 × 10³ kg/m³
Density = Specific gravity × density of water = 2.5 × 1000 = 2.5 × 10³ kg/m³.
Density = Specific gravity × density of water = 2.5 × 1000 = 2.5 × 10³ kg/m³.
9
The dimension of thermal conductivity is:
(2025, 2023)
Correct Answer: C. MLT⁻³K⁻¹
From Q/t = kAΔT/d, the dimensional formula of thermal conductivity is [MLT⁻³K⁻¹].
From Q/t = kAΔT/d, the dimensional formula of thermal conductivity is [MLT⁻³K⁻¹].
10
The SI unit of universal gas constant (R) is:
(2023)
Correct Answer: C. J mole⁻¹ K⁻¹
From PV = nRT, R = PV/nT. Since PV represents energy in joules, the SI unit is J mole⁻¹ K⁻¹.
From PV = nRT, R = PV/nT. Since PV represents energy in joules, the SI unit is J mole⁻¹ K⁻¹.
UNIT 2: Force and Motion
1
A gun of mass 10 kg fires a bullet of mass 40 g with a speed of 400 m/s. The recoil velocity of the gun is:
(2026, 2025)
Correct Answer: A. 1.6 m/s
By conservation of linear momentum:
v = −(0.04 × 400)/10 = −1.6 m/s.
Hence the magnitude of recoil velocity is 1.6 m/s.
By conservation of linear momentum:
v = −(0.04 × 400)/10 = −1.6 m/s.
Hence the magnitude of recoil velocity is 1.6 m/s.
2
The force acting on a particle of mass 10 g that accelerates by 20 m/s² is:
(2026)
Correct Answer: C. 20000 dyne
F = ma = 0.01 × 20 = 0.2 N.
Since 1 N = 10⁵ dyne, F = 0.2 × 10⁵ = 20000 dyne.
F = ma = 0.01 × 20 = 0.2 N.
Since 1 N = 10⁵ dyne, F = 0.2 × 10⁵ = 20000 dyne.
3
The angular velocity of the second hand of a clock is:
(2026, 2023)
Correct Answer: B. π/30 rad/s
The second hand completes 2π radians in 60 seconds.
ω = 2π/60 = π/30 rad/s.
The second hand completes 2π radians in 60 seconds.
ω = 2π/60 = π/30 rad/s.
4
The rate of change of linear momentum with respect to time is called:
(2025)
Correct Answer: B. force
According to Newton’s second law, F = dp/dt.
According to Newton’s second law, F = dp/dt.
5
A ball of mass 5 kg strikes a wall with a speed of 10 m/s and rebounds with the same speed. The change in linear momentum of the ball is:
(2025, 2023)
Correct Answer: C. 100 kg-m/s
Initial momentum = 5 × 10 = 50 kg·m/s.
Final momentum = −50 kg·m/s.
Change = −50 − 50 = −100 kg·m/s.
Magnitude = 100 kg·m/s.
Initial momentum = 5 × 10 = 50 kg·m/s.
Final momentum = −50 kg·m/s.
Change = −50 − 50 = −100 kg·m/s.
Magnitude = 100 kg·m/s.
6
A bullet is fired from a gun. If the gun recoils, the magnitude of the linear momentum of the gun is:
(2025)
Correct Answer: C. equal to that of bullet
By conservation of linear momentum, the gun and bullet have equal momentum in magnitude but opposite in direction.
By conservation of linear momentum, the gun and bullet have equal momentum in magnitude but opposite in direction.
7
The direction of the angular velocity vector is along:
(2025)
Correct Answer: D. the axis of rotation
Angular velocity is an axial vector and is directed along the axis of rotation. Its exact direction is determined by the Right-Hand Rule.
Angular velocity is an axial vector and is directed along the axis of rotation. Its exact direction is determined by the Right-Hand Rule.
8
The angular velocity of 30 r.p.m. can be expressed in rad/s as:
(2025)
Correct Answer: A. π rad/s
ω = N × 2π / 60 = 30 × 2π / 60 = π rad/s.
ω = N × 2π / 60 = 30 × 2π / 60 = π rad/s.
9
The angle of banking is independent of:
(2024)
Correct Answer: D. mass of vehicle
For banking, tan θ = v²/(rg). Mass does not appear in the formula.
For banking, tan θ = v²/(rg). Mass does not appear in the formula.
10
Newton-second (N s) is the unit of:
(2024)
Correct Answer: B. Momentum
Impulse = Force × time = N·s. By the impulse-momentum theorem, N·s is equivalent to kg·m/s, the unit of linear momentum.
Impulse = Force × time = N·s. By the impulse-momentum theorem, N·s is equivalent to kg·m/s, the unit of linear momentum.
11
Rocket propulsion is based on the principle of conservation of:
(2023)
Correct Answer: B. linear momentum
Rocket propulsion works through conservation of linear momentum. High-velocity gases are expelled backward, giving the rocket forward momentum.
Rocket propulsion works through conservation of linear momentum. High-velocity gases are expelled backward, giving the rocket forward momentum.
12
When milk is churned, cream separates out because of:
(2023)
Correct Answer: D. centrifugal force
Churning involves rapid rotation. Centrifugal effects help separate the lighter cream from the heavier components of milk.
Churning involves rapid rotation. Centrifugal effects help separate the lighter cream from the heavier components of milk.
UNIT 3: Work, Power and Energy
1
A body performs 600 J of work in 30 s. Its power is:
(2026)
Correct Answer: A. 20 W
Power = Work / Time = 600/30 = 20 W.
Power = Work / Time = 600/30 = 20 W.
2
The relation between kinetic energy (E) and linear momentum (P) is:
(2025)
Correct Answer: B. P = √(2mE)
E = P²/(2m). Therefore, P² = 2mE and P = √(2mE).
E = P²/(2m). Therefore, P² = 2mE and P = √(2mE).
3
If the kinetic energy of a body increases by 100%, then its momentum increases by:
(2024)
Correct Answer: C. 41%
P = √(2mE). If E becomes 2E, momentum becomes √2P ≈ 1.414P. Thus the percentage increase is approximately 41.4%, or 41%.
P = √(2mE). If E becomes 2E, momentum becomes √2P ≈ 1.414P. Thus the percentage increase is approximately 41.4%, or 41%.
4
In an inclined plane, the relationship between the angle of friction (θ) and angle of repose (φ) is:
(2024)
Correct Answer: C. θ = φ
For both angles, μ = tan θ = tan φ. Hence θ = φ.
For both angles, μ = tan θ = tan φ. Hence θ = φ.
5
What energy transformation takes place when you turn on an electric light?
(2024)
Correct Answer: D. Electrical → light + heat
Electrical energy is converted primarily into light and partly into heat.
Electrical energy is converted primarily into light and partly into heat.
6
What is the shape of the graph between the speed and kinetic energy of a body?
(2023)
Correct Answer: C. parabola
Kinetic energy E = ½mv². Therefore E is proportional to v², giving a parabolic graph.
Kinetic energy E = ½mv². Therefore E is proportional to v², giving a parabolic graph.
7
The ratio of kinetic energy of two bodies of mass m and 4m is 2:1. The ratio of their linear momentum will be:
(2023)
Correct Answer: A. 1:√2
P = √(2mE). Therefore, P₁/P₂ = √[(m/4m) × (2/1)] = 1/√2 = 1:√2.
P = √(2mE). Therefore, P₁/P₂ = √[(m/4m) × (2/1)] = 1/√2 = 1:√2.
UNIT 4: Rotational Motion
1
The moment of inertia of a disc about an axis passing through its centre and perpendicular to its plane is (1/2)MR². Its moment of inertia about its diameter is:
(2026)
Correct Answer: D. (1/4)MR²
By the perpendicular axis theorem, Iz = Ix + Iy. For a symmetric disc, Ix = Iy. Therefore, (1/2)MR² = 2I, giving I = (1/4)MR².
By the perpendicular axis theorem, Iz = Ix + Iy. For a symmetric disc, Ix = Iy. Therefore, (1/2)MR² = 2I, giving I = (1/4)MR².
2
The dimensional formula of torque is:
(2024)
Correct Answer: A. [ML²T⁻²]
Torque τ = r × F.
Therefore [τ] = [L][MLT⁻²] = [ML²T⁻²].
Torque τ = r × F.
Therefore [τ] = [L][MLT⁻²] = [ML²T⁻²].
3
On which of the following factor the moment of inertia of an object does not depend?
(2024)
Correct Answer: B. Angular velocity
Moment of inertia I = Σmr². It depends on mass, mass distribution and axis, but not on angular velocity.
Moment of inertia I = Σmr². It depends on mass, mass distribution and axis, but not on angular velocity.
4
The angular momentum (L) of a rigid body of moment of inertia I and angular velocity ω is equal to:
(2024)
Correct Answer: A. L = Iω
Angular momentum is given by L = Iω.
Angular momentum is given by L = Iω.
5
The moment of inertia of a ring about an axis passing through the centre and perpendicular to the plane of the ring is MR². What will be the moment of inertia of the ring about its tangent in its plane?
(2023)
Correct Answer: C. (3/2)MR²
By the perpendicular axis theorem, the MI about a diameter is (1/2)MR². Using the parallel axis theorem: Itangent = (1/2)MR² + MR² = (3/2)MR².
By the perpendicular axis theorem, the MI about a diameter is (1/2)MR². Using the parallel axis theorem: Itangent = (1/2)MR² + MR² = (3/2)MR².
6
If moment of inertia = I, angular velocity = ω, angular acceleration = α, torque = τ, then which of the following relation is correct?
(2023)
Correct Answer: A. τ = Iα
Torque is the rotational analogue of force. Therefore τ = Iα.
Torque is the rotational analogue of force. Therefore τ = Iα.
UNIT 5: Properties of Matter
1
The slope of a stress-strain curve in the elastic region of a steel wire gives:
(2026)
Correct Answer: B. Young’s modulus
In the elastic region, Young’s modulus is the ratio of stress to strain. Thus, the slope of the stress-strain curve represents Young’s modulus.
In the elastic region, Young’s modulus is the ratio of stress to strain. Thus, the slope of the stress-strain curve represents Young’s modulus.
2
The strain developed in a steel rod of length 5 m that is extended by 1 m is:
(2026)
Correct Answer: C. 0.2
Strain = ΔL/L = 1/5 = 0.2.
Strain = ΔL/L = 1/5 = 0.2.
3
The capillary rise phenomenon occurs due to:
(2026)
Correct Answer: D. surface tension
Capillary rise is associated with adhesive/cohesive forces and surface tension.
Capillary rise is associated with adhesive/cohesive forces and surface tension.
4
In a horizontal pipe, water is flowing at a speed of 10 cm/s. What will be the speed if the radius of the pipe is doubled?
(2026, 2025)
Correct Answer: A. 2.5 cm/s
By continuity, A₁v₁ = A₂v₂. Since A ∝ r², doubling the radius makes the area four times. Therefore v₂ = 10/4 = 2.5 cm/s.
By continuity, A₁v₁ = A₂v₂. Since A ∝ r², doubling the radius makes the area four times. Therefore v₂ = 10/4 = 2.5 cm/s.
5
Among the following substances, which one is the most elastic?
(2025)
Correct Answer: C. steel
Steel has a much larger Young’s modulus than the other listed materials and therefore resists deformation strongly.
Steel has a much larger Young’s modulus than the other listed materials and therefore resists deformation strongly.
6
The S.I. unit of surface tension is:
(2025)
Correct Answer: A. Nm⁻¹
Surface tension = Force/Length. Therefore its SI unit is N/m or Nm⁻¹.
Surface tension = Force/Length. Therefore its SI unit is N/m or Nm⁻¹.
7
The rise of a liquid in a capillary tube depends on:
(2025)
Source Answer: D. inner radius of the tube (and C)
According to Jurin’s law, h = 2Tcosθ/(rρg). Thus capillary rise is inversely proportional to the inner radius and is also affected by the nature of the liquid through T and ρ.
According to Jurin’s law, h = 2Tcosθ/(rρg). Thus capillary rise is inversely proportional to the inner radius and is also affected by the nature of the liquid through T and ρ.
8
A load of 98 N is suspended by a wire of length 1 m and cross-sectional area 0.10 cm². The longitudinal stress developed is:
(2024)
Correct Answer: B. 9.8 × 10⁶ N/m²
0.10 cm² = 10⁻⁵ m².
Stress = F/A = 98/10⁻⁵ = 9.8 × 10⁶ N/m².
0.10 cm² = 10⁻⁵ m².
Stress = F/A = 98/10⁻⁵ = 9.8 × 10⁶ N/m².
9
When a detergent is added to water, its surface tension:
(2024)
Correct Answer: A. decreases
Detergent acts as a surface-active agent and reduces the surface tension of water.
Detergent acts as a surface-active agent and reduces the surface tension of water.
10
What is the relation between the viscosity of Blood and Water?
(2024)
Correct Answer: B. Blood is more viscous than water
Blood has greater internal friction because it contains cells, proteins and other components.
Blood has greater internal friction because it contains cells, proteins and other components.
11
The S.I. unit of stress is:
(2023)
Correct Answer: C. Nm⁻²
Stress = Force/Area. Therefore its SI unit is N/m², also called Pascal.
Stress = Force/Area. Therefore its SI unit is N/m², also called Pascal.
12
A mass of liquid is stirred and then allowed to settle. The liquid ultimately comes to rest because of:
(2023)
Correct Answer: B. viscosity
Viscosity produces internal friction between adjacent layers and opposes their relative motion, eventually bringing the liquid to rest.
Viscosity produces internal friction between adjacent layers and opposes their relative motion, eventually bringing the liquid to rest.
13
The longitudinal strain of a wire is 0.5 × 10⁻³ and its Poisson’s ratio is 0.2. The value of the lateral strain of the wire is:
(2023)
Correct Answer: B. 10⁻⁴
Lateral strain = Poisson’s ratio × longitudinal strain = 0.2 × 0.5 × 10⁻³ = 10⁻⁴.
Lateral strain = Poisson’s ratio × longitudinal strain = 0.2 × 0.5 × 10⁻³ = 10⁻⁴.
14
Young’s modulus of a perfectly rigid body is:
(2023)
Correct Answer: D. infinity
For a perfectly rigid body, strain is zero. Since Y = stress/strain, Young’s modulus tends to infinity.
For a perfectly rigid body, strain is zero. Since Y = stress/strain, Young’s modulus tends to infinity.
15
A uniform rod of mass m, length l, cross-section A, and Young’s modulus Y hangs from a ceiling. Its elongation under its own weight will be:
(2023)
Correct Answer: C. mgl/2AY
The tension varies from mg at the top to zero at the bottom. Average tension is mg/2. Therefore elongation = (mg/2 × l)/(AY) = mgl/(2AY).
The tension varies from mg at the top to zero at the bottom. Average tension is mg/2. Therefore elongation = (mg/2 × l)/(AY) = mgl/(2AY).
16
Hooke’s law is valid within:
(2023)
Correct Answer: B. elastic limit
Hooke’s law states that stress is directly proportional to strain within the elastic limit.
Hooke’s law states that stress is directly proportional to strain within the elastic limit.
17
Bernoulli’s Theorem in fluid dynamics is another form of the law of conservation of:
(2023)
Correct Answer: C. energy
Bernoulli’s theorem expresses conservation of mechanical energy for an ideal flowing fluid.
Bernoulli’s theorem expresses conservation of mechanical energy for an ideal flowing fluid.
18
The height of liquid in a capillary tube of radius r is h. The height of the liquid in another capillary tube of same material but of radius r/2 is:
(2023)
Correct Answer: C. 2h
By Jurin’s law, h ∝ 1/r. If radius becomes r/2, the height becomes 2h.
By Jurin’s law, h ∝ 1/r. If radius becomes r/2, the height becomes 2h.
19
The rise of liquid in a capillary tube is directly proportional to:
(2023)
Correct Answer: C. surface tension of the liquid
From h = 2Tcosθ/(rρg), capillary rise is directly proportional to surface tension T.
From h = 2Tcosθ/(rρg), capillary rise is directly proportional to surface tension T.
UNIT 6: Heat and Thermometry
1
Heat is supplied to two identical gases to raise equal temperature. One is kept at constant volume (Cv) and the other at constant pressure (Cp). Which gas absorbs more heat?
(2026)
Correct Answer: B. Constant pressure
At constant pressure, the gas expands and performs work, so additional heat is required. Hence Cp > Cv and the constant-pressure gas absorbs more heat.
At constant pressure, the gas expands and performs work, so additional heat is required. Hence Cp > Cv and the constant-pressure gas absorbs more heat.
2
The difference of temperature of two bodies in Celsius scale is 25°C. In Fahrenheit scale this difference will be:
(2026, 2023)
Correct Answer: A. 45°
For temperature intervals, ΔF = 1.8 × ΔC. Therefore ΔF = 1.8 × 25 = 45°F.
For temperature intervals, ΔF = 1.8 × ΔC. Therefore ΔF = 1.8 × 25 = 45°F.
3
The S.I. unit of thermal conductivity (k) is:
(2026)
Correct Answer: A. Watt m⁻¹ K⁻¹
From Q/t = kAΔT/d, the SI unit of thermal conductivity is W m⁻¹ K⁻¹.
From Q/t = kAΔT/d, the SI unit of thermal conductivity is W m⁻¹ K⁻¹.
4
At what temperature do the Celsius and Fahrenheit scales show the same reading?
(2025, 2024)
Correct Answer: C. -40°
Using C/5 = (F−32)/9 and putting C = F = x gives x = −40. Thus both scales show the same reading at −40°.
Using C/5 = (F−32)/9 and putting C = F = x gives x = −40. Thus both scales show the same reading at −40°.
5
Which of the following statement is true regarding the specific heats of gases?
(2025)
Correct Answer: B. Cp > Cv
For one mole of an ideal gas, Mayer’s relation is Cp − Cv = R. Since R is positive, Cp > Cv.
For one mole of an ideal gas, Mayer’s relation is Cp − Cv = R. Since R is positive, Cp > Cv.
6
While deducing Mayer’s relation Cp – Cv = R, the amount of gas taken should be:
(2024)
Correct Answer: C. 1 mole
The relation Cp − Cv = R is the molar form. For n moles, the corresponding relation is Cp − Cv = nR.
The relation Cp − Cv = R is the molar form. For n moles, the corresponding relation is Cp − Cv = nR.
7
The internal energy of an ideal gas depends exclusively on its:
(2023)
Correct Answer: C. temperature
For an ideal gas, internal energy is a function of absolute temperature only.
For an ideal gas, internal energy is a function of absolute temperature only.
8
Which mode of heat transfer absolutely requires gravity to operate?
(2023)
Correct Answer: B. Convection
Natural convection depends on buoyancy. Under gravity, warmer less-dense fluid rises and cooler denser fluid sinks.
Natural convection depends on buoyancy. Under gravity, warmer less-dense fluid rises and cooler denser fluid sinks.