Physics
Q. A cyclist travels at a speed of 10 m/s for 5 seconds. What distance does he cover? (2023)
A.
25 m
B.
50 m
C.
75 m
D.
100 m
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Solution
Distance = speed * time = 10 m/s * 5 s = 50 m.
Correct Answer: B — 50 m
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Q. A cylinder rolls down an incline without slipping. If its mass is M and radius is R, what is the acceleration of its center of mass? (2020)
A.
g/2
B.
g/3
C.
g/4
D.
g/5
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Solution
For rolling without slipping, a_cm = (2/3)g sin(θ).
Correct Answer: B — g/3
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Q. A disc of radius R and mass M is rotating about its axis with an angular velocity ω. What is its rotational kinetic energy? (2020)
A.
(1/2)Iω²
B.
(1/2)Mω²
C.
Iω
D.
Mω²
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Solution
Rotational kinetic energy K.E. = (1/2)Iω². For a disc, I = (1/2)MR², thus K.E. = (1/4)MR²ω².
Correct Answer: A — (1/2)Iω²
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Q. A flywheel has a moment of inertia I and is rotating with an angular velocity ω. If a torque τ is applied, what is the angular acceleration? (2021)
A.
τ/I
B.
I/τ
C.
ω/τ
D.
Iω
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Solution
From Newton's second law for rotation, τ = Iα, thus α = τ/I.
Correct Answer: A — τ/I
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Q. A force of 10 N is applied to an object, causing it to accelerate at 2 m/s². What is the mass of the object? (2020)
A.
5 kg
B.
10 kg
C.
15 kg
D.
20 kg
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Solution
Using F = ma, mass m = F/a = 10 N / 2 m/s² = 5 kg.
Correct Answer: A — 5 kg
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Q. A force of 10 N is applied to move a box 5 m across a floor. What is the work done on the box?
A.
10 J
B.
20 J
C.
50 J
D.
5 J
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Solution
Work done = Force × Distance = 10 N × 5 m = 50 J
Correct Answer: B — 20 J
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Q. A force of 10 N is applied to move a box 5 m along a horizontal surface. What is the work done by the force? (2021)
A.
20 J
B.
50 J
C.
10 J
D.
5 J
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Solution
Work done = Force × Distance = 10 N × 5 m = 50 J
Correct Answer: B — 50 J
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Q. A force of 10 N is applied to move an object 5 m. What is the work done? (2023)
A.
50 J
B.
10 J
C.
5 J
D.
20 J
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Solution
Work done = Force × Distance = 10 N × 5 m = 50 J.
Correct Answer: A — 50 J
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Q. A force of 30 N is applied to a 6 kg object. What is the object's acceleration? (2023)
A.
3 m/s²
B.
4 m/s²
C.
5 m/s²
D.
6 m/s²
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Solution
Using F = ma, we find a = F/m = 30 N / 6 kg = 5 m/s².
Correct Answer: B — 4 m/s²
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Q. A force of 50 N is applied to move an object 4 m. How much work is done?
A.
100 J
B.
150 J
C.
200 J
D.
250 J
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Solution
Work = Force * Distance = 50 N * 4 m = 200 J.
Correct Answer: C — 200 J
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Q. A gas expands from 2 L to 5 L at a constant pressure of 1 atm. How much work is done by the gas? (2023)
A.
3 L·atm
B.
5 L·atm
C.
2 L·atm
D.
1 L·atm
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Solution
Work done by the gas during expansion at constant pressure is W = PΔV. Here, ΔV = 5 L - 2 L = 3 L, so W = 1 atm * 3 L = 3 L·atm.
Correct Answer: A — 3 L·atm
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Q. A gas expands isothermally at 300 K and absorbs 600 J of heat. What is the work done by the gas? (2023)
A.
600 J
B.
300 J
C.
900 J
D.
0 J
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Solution
In an isothermal process, the work done by the gas is equal to the heat absorbed. Therefore, work done = 600 J.
Correct Answer: A — 600 J
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Q. A gas expands isothermally at 300 K from a volume of 1 m³ to 2 m³. If the pressure of the gas is 100 kPa, what is the work done by the gas? (2020)
A.
0 kJ
B.
10 kJ
C.
20 kJ
D.
30 kJ
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Solution
Work done (W) = P * ΔV = 100 kPa * (2 m³ - 1 m³) = 100 kPa * 1 m³ = 100 kJ = 10 kJ.
Correct Answer: B — 10 kJ
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Q. A gas is compressed isothermally from a volume of 4 L to 1 L at a constant temperature of 300 K. If the initial pressure is 1 atm, what is the final pressure?
A.
4 atm
B.
3 atm
C.
2 atm
D.
1 atm
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Solution
Using Boyle's Law, P1V1 = P2V2, we find P2 = P1 * (V1/V2) = 1 atm * (4 L / 1 L) = 4 atm.
Correct Answer: A — 4 atm
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Q. A light ray strikes a plane mirror at an angle of incidence of 30 degrees. What is the angle of reflection? (2021)
A.
30 degrees
B.
60 degrees
C.
90 degrees
D.
45 degrees
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Solution
According to the law of reflection, the angle of reflection is equal to the angle of incidence. Therefore, the angle of reflection is also 30 degrees.
Correct Answer: A — 30 degrees
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Q. A machine does 1200 J of work in 60 seconds. What is its efficiency if the input energy is 2000 J? (2022)
A.
60%
B.
70%
C.
80%
D.
90%
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Solution
Efficiency = (Output Work / Input Energy) * 100 = (1200 J / 2000 J) * 100 = 60%.
Correct Answer: A — 60%
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Q. A mass attached to a spring oscillates with a frequency of 2 Hz. What is the period of the oscillation?
A.
0.5 s
B.
1 s
C.
2 s
D.
4 s
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Solution
The period T is the reciprocal of frequency f. Thus, T = 1/f = 1/2 = 0.5 s.
Correct Answer: B — 1 s
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Q. A mass attached to a spring oscillates with a period of 2 seconds. What is its frequency? (2014)
A.
0.5 Hz
B.
1 Hz
C.
2 Hz
D.
4 Hz
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Solution
Frequency f = 1/T = 1/2 s = 0.5 Hz.
Correct Answer: A — 0.5 Hz
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Q. A mass m is attached to a string of length L and is swung in a vertical circle. What is the tension in the string at the top of the circle? (2023)
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Solution
At the top, T + mg = mv²/L. T = mv²/L - mg.
Correct Answer: A — mg
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Q. A mass-spring system oscillates with a frequency of 1 Hz. What is the angular frequency? (2023)
A.
2π rad/s
B.
π rad/s
C.
1 rad/s
D.
4π rad/s
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Solution
Angular frequency ω is related to frequency f by ω = 2πf. Therefore, for f = 1 Hz, ω = 2π(1) = 2π rad/s.
Correct Answer: A — 2π rad/s
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Q. A mass-spring system oscillates with a frequency of 5 Hz. What is the angular frequency? (2021)
A.
10π rad/s
B.
5π rad/s
C.
2π rad/s
D.
20π rad/s
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Solution
Angular frequency ω = 2πf = 2π × 5 Hz = 10π rad/s.
Correct Answer: A — 10π rad/s
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Q. A mass-spring system oscillates with an amplitude of 0.1 m. What is the maximum speed of the mass if the angular frequency is 20 rad/s?
A.
1 m/s
B.
2 m/s
C.
3 m/s
D.
4 m/s
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Solution
The maximum speed v_max is given by v_max = Aω, where A is the amplitude and ω is the angular frequency. Thus, v_max = 0.1 * 20 = 2 m/s.
Correct Answer: B — 2 m/s
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Q. A parallel plate capacitor has a capacitance of 5 µF. If the potential difference across it is increased from 10 V to 20 V, what is the change in stored energy?
A.
25 µJ
B.
50 µJ
C.
75 µJ
D.
100 µJ
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Solution
Energy U = 1/2 C V^2. Initial U = 1/2 * 5 × 10^-6 * 10^2 = 0.025 J; Final U = 1/2 * 5 × 10^-6 * 20^2 = 0.1 J. Change = 0.1 - 0.025 = 0.075 J = 75 µJ.
Correct Answer: B — 50 µJ
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Q. A particle is moving in a circle of radius r with a constant speed v. What is the angular velocity? (2022)
A.
v/r
B.
r/v
C.
vr
D.
v²/r
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Solution
Angular velocity ω = v/r.
Correct Answer: A — v/r
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Q. A particle moves in a circular path of radius r with a constant speed v. What is the centripetal acceleration? (2022)
A.
v²/r
B.
vr
C.
r/v
D.
v/r
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Solution
Centripetal acceleration a_c = v²/r.
Correct Answer: A — v²/r
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Q. A pendulum completes 20 oscillations in 40 seconds. What is its frequency? (2022)
A.
0.5 Hz
B.
1 Hz
C.
2 Hz
D.
4 Hz
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Solution
Frequency f = number of oscillations / time = 20 / 40 s = 0.5 Hz.
Correct Answer: B — 1 Hz
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Q. A pendulum swings back and forth. At which point is its potential energy maximum?
A.
At the lowest point
B.
At the highest point
C.
At the midpoint
D.
At all points
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Solution
The potential energy of a pendulum is maximum at the highest point of its swing, where its kinetic energy is minimum.
Correct Answer: B — At the highest point
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Q. A pendulum swings with a maximum angle of 30 degrees. What is the approximate time period for small angles? (2022)
A.
1.0 s
B.
0.5 s
C.
2.0 s
D.
0.25 s
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Solution
For small angles, T ≈ 2π√(L/g). Assuming L = 1 m, T ≈ 2π√(1/9.8) ≈ 2.0 s.
Correct Answer: A — 1.0 s
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Q. A person lifts a 10 kg box to a height of 2 m. What is the work done against gravity? (g = 9.8 m/s²)
A.
196 J
B.
98 J
C.
20 J
D.
10 J
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Solution
Work = mgh = 10 kg * 9.8 m/s² * 2 m = 196 J.
Correct Answer: A — 196 J
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Q. A ray of light passes from air into glass at an angle of 45 degrees. What is the angle of refraction if the refractive index of glass is 1.5? (2022)
A.
30 degrees
B.
45 degrees
C.
60 degrees
D.
90 degrees
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Solution
Using Snell's law, n1 * sin(theta1) = n2 * sin(theta2). Here, n1 = 1 (air), theta1 = 45 degrees, n2 = 1.5 (glass). Thus, sin(theta2) = (1 * sin(45))/1.5 = 0.471, giving theta2 ≈ 30 degrees.
Correct Answer: A — 30 degrees
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