Q. A projectile is launched at an angle of 30 degrees with an initial speed of 20 m/s. What is the maximum height it reaches? (2022)
A.
5 m
B.
10 m
C.
15 m
D.
20 m
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Solution
Using the formula: H = (u² * sin²θ) / (2g). H = (20² * (1/2)) / (2 * 9.8) = 10.2 m, approximately 10 m.
Correct Answer: B — 10 m
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Q. A ray of light passes through the center of curvature of a concave mirror. What will be the nature of the image formed? (2020)
A.
Real and inverted
B.
Virtual and erect
C.
Real and erect
D.
Virtual and inverted
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Solution
When a ray passes through the center of curvature, it reflects back on itself, forming a real and inverted image at the same distance as the object.
Correct Answer: A — Real and inverted
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Q. A ray of light strikes a glass surface at an angle of incidence of 30 degrees. If the refractive index of glass is 1.5, what is the angle of refraction? (2022)
A.
20 degrees
B.
30 degrees
C.
40 degrees
D.
50 degrees
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Solution
Using Snell's law, n1 * sin(i) = n2 * sin(r). Here, n1 = 1 (air), i = 30 degrees, n2 = 1.5 (glass). Therefore, sin(r) = (1 * sin(30))/1.5 = 0.333. Thus, r = sin^(-1)(0.333) ≈ 19.5 degrees, which is approximately 20 degrees.
Correct Answer: A — 20 degrees
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Q. A ray of light strikes a plane surface at an angle of incidence of 30 degrees. What is the angle of reflection? (2023)
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 30 degrees.
Correct Answer: A — 30 degrees
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Q. A rotating body has an angular momentum L. If its moment of inertia is doubled and angular velocity is halved, what will be the new angular momentum? (2021)
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Solution
New angular momentum L' = I'ω' = (2I)(ω/2) = L.
Correct Answer: A — L/2
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Q. A rotating object has a moment of inertia of 5 kg·m² and is rotating with an angular velocity of 4 rad/s. What is its kinetic energy? (2022)
A.
40 J
B.
20 J
C.
10 J
D.
80 J
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Solution
The rotational kinetic energy is given by KE = (1/2)Iω² = (1/2)(5 kg·m²)(4 rad/s)² = 40 J.
Correct Answer: A — 40 J
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Q. A solid cylinder and a hollow cylinder of the same mass and radius are released from rest at the same height. Which one reaches the ground first? (2022)
A.
Solid cylinder
B.
Hollow cylinder
C.
Both reach at the same time
D.
Depends on the height
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Solution
The solid cylinder has a lower moment of inertia, thus it accelerates faster and reaches the ground first.
Correct Answer: A — Solid cylinder
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Q. A solid sphere and a hollow sphere of the same mass and radius are rolling down an incline. Which one will reach the bottom first? (2021)
A.
Solid sphere
B.
Hollow sphere
C.
Both will reach at the same time
D.
It depends on the angle of incline
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Solution
The solid sphere has a smaller moment of inertia compared to the hollow sphere, allowing it to accelerate faster down the incline.
Correct Answer: A — Solid sphere
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Q. A solid sphere of mass M and radius R rolls without slipping down an inclined plane of height h. What is the speed of the center of mass of the sphere when it reaches the bottom? (2021)
A.
√(2gh)
B.
√(5gh/7)
C.
√(3gh/5)
D.
√(gh)
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Solution
Using conservation of energy, potential energy at the top = kinetic energy at the bottom. The total kinetic energy is the sum of translational and rotational kinetic energy. Thus, v = √(5gh/7).
Correct Answer: B — √(5gh/7)
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Q. A sound wave travels through air at a speed of 340 m/s. What is the wavelength of a sound wave with a frequency of 1700 Hz? (2022)
A.
0.2 m
B.
0.5 m
C.
1.0 m
D.
2.0 m
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Solution
Using the formula λ = v/f, where v is the speed and f is the frequency, we have λ = 340 m/s / 1700 Hz = 0.2 m.
Correct Answer: A — 0.2 m
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Q. A spring is compressed by 0.1 m and has a spring constant of 200 N/m. What is the potential energy stored in the spring? (2019)
A.
1 J
B.
2 J
C.
0.5 J
D.
4 J
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Solution
Potential Energy (PE) = 1/2 * k * x^2 = 1/2 * 200 N/m * (0.1 m)^2 = 1 J
Correct Answer: A — 1 J
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Q. A spring is compressed by 0.2 m and has a spring constant of 500 N/m. What is the potential energy stored in the spring? (2023)
A.
10 J
B.
5 J
C.
20 J
D.
2 J
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Solution
Potential Energy in Spring (PE) = 1/2 kx^2 = 1/2 * 500 N/m * (0.2 m)^2 = 10 J
Correct Answer: A — 10 J
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Q. A stone is thrown downward with an initial velocity of 5 m/s from a height of 45 m. How long will it take to hit the ground? (2020)
A.
3 s
B.
4 s
C.
5 s
D.
6 s
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Solution
Using the equation of motion: h = ut + 0.5gt². Solving for t gives t ≈ 4 seconds.
Correct Answer: B — 4 s
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Q. A torque τ is applied to a rigid body with a moment of inertia I. If the torque is doubled, what happens to the angular acceleration? (2019)
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
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Solution
According to Newton's second law for rotation, τ = Iα. If τ is doubled, α also doubles.
Correct Answer: A — It doubles
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Q. A train starts from rest and accelerates uniformly at 2 m/s². What is its speed after 10 seconds? (2021)
A.
10 m/s
B.
20 m/s
C.
30 m/s
D.
40 m/s
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Solution
Using the formula: final velocity = initial velocity + acceleration * time. Final velocity = 0 + 2 * 10 = 20 m/s.
Correct Answer: B — 20 m/s
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Q. A tuning fork vibrates at a frequency of 440 Hz. What is the time period of its vibration? (2020)
A.
0.00227 s
B.
0.0045 s
C.
0.01 s
D.
0.005 s
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Solution
Time period (T) = 1 / frequency = 1 / 440 Hz ≈ 0.00227 s
Correct Answer: A — 0.00227 s
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Q. A tuning fork vibrates at a frequency of 440 Hz. What is the time period of the tuning fork? (2020)
A.
0.00227 s
B.
0.0045 s
C.
0.01 s
D.
0.005 s
Show solution
Solution
Time period (T) = 1 / frequency = 1 / 440 Hz ≈ 0.00227 s.
Correct Answer: A — 0.00227 s
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Q. A uniform rod of length L and mass M is pivoted at one end and released from rest. What is the angular speed of the rod just before it hits the ground? (2019)
A.
√(3g/L)
B.
√(2g/L)
C.
√(g/L)
D.
√(4g/L)
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Solution
Using conservation of energy, potential energy at the top converts to rotational kinetic energy at the bottom. The angular speed ω = √(3g/L).
Correct Answer: B — √(2g/L)
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Q. A wave has a frequency of 50 Hz and a wavelength of 2 m. What is the speed of the wave? (2021)
A.
25 m/s
B.
50 m/s
C.
100 m/s
D.
200 m/s
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Solution
The speed of a wave is given by the formula v = fλ. Here, v = 50 Hz * 2 m = 100 m/s.
Correct Answer: B — 50 m/s
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Q. A wave has a frequency of 500 Hz and a wavelength of 0.5 m. What is the speed of the wave? (2023)
A.
250 m/s
B.
500 m/s
C.
1000 m/s
D.
2000 m/s
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Solution
The speed of the wave can be calculated using the formula v = fλ. Here, v = 500 Hz * 0.5 m = 250 m/s.
Correct Answer: B — 500 m/s
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Q. A wave has a frequency of 500 Hz and a wavelength of 0.68 m. What is the speed of the wave? (2021)
A.
340 m/s
B.
500 m/s
C.
680 m/s
D.
250 m/s
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Solution
The speed of the wave can be calculated using the formula v = fλ. Thus, v = 500 Hz * 0.68 m = 340 m/s.
Correct Answer: A — 340 m/s
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Q. A wheel is rotating with an angular velocity of 10 rad/s. If it accelerates at 2 rad/s², what will be its angular velocity after 5 seconds? (2023)
A.
20 rad/s
B.
10 rad/s
C.
15 rad/s
D.
25 rad/s
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Solution
Using the formula ω = ω₀ + αt, we have ω = 10 rad/s + (2 rad/s²)(5 s) = 20 rad/s.
Correct Answer: A — 20 rad/s
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Q. A wheel of radius R and mass M is rolling without slipping on a horizontal surface. If it has a linear speed v, what is its total kinetic energy? (2022)
A.
(1/2)Mv²
B.
(1/2)Mv² + (1/2)(Iω²)
C.
(1/2)Mv² + (1/2)(Mv²)
D.
(1/2)Mv² + (1/2)(Mv²/2)
Show solution
Solution
The total kinetic energy is the sum of translational and rotational kinetic energy. K.E. = (1/2)Mv² + (1/2)(Iω²) where I = (1/2)MR² for a solid cylinder.
Correct Answer: B — (1/2)Mv² + (1/2)(Iω²)
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Q. A wire of length L and diameter d is stretched by a force F. If the diameter is halved, what will be the new elongation for the same force? (2020)
A.
It will double
B.
It will quadruple
C.
It will remain the same
D.
It will halve
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Solution
Elongation is inversely proportional to the area. Halving the diameter reduces the area to a quarter, thus elongation quadruples.
Correct Answer: B — It will quadruple
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Q. A wire of length L and diameter d is stretched by a force F. If the diameter is halved while keeping the length constant, what happens to the stress? (2020)
A.
It doubles
B.
It quadruples
C.
It halves
D.
It remains the same
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Solution
Stress = Force / Area. Halving the diameter increases the area by a factor of 1/4, thus stress quadruples.
Correct Answer: B — It quadruples
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Q. A wire of length L and diameter d is stretched by a force F. What is the expression for the elongation of the wire? (2020)
A.
(F * L) / (A * Y)
B.
(F * Y) / (A * L)
C.
(Y * A) / (F * L)
D.
(L * d) / (F * Y)
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Solution
Elongation (ΔL) = (F * L) / (A * Y), where A is the cross-sectional area and Y is Young's modulus.
Correct Answer: A — (F * L) / (A * Y)
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Q. According to Bernoulli's equation, an increase in the speed of a fluid occurs simultaneously with a: (2020)
A.
Increase in pressure
B.
Decrease in pressure
C.
Increase in temperature
D.
Decrease in density
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Solution
Bernoulli's equation states that an increase in the speed of a fluid results in a decrease in pressure.
Correct Answer: B — Decrease in pressure
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Q. According to Bernoulli's principle, an increase in the speed of a fluid occurs simultaneously with a: (2020)
A.
Increase in pressure
B.
Decrease in pressure
C.
Increase in temperature
D.
Decrease in density
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Solution
Bernoulli's principle states that an increase in the speed of a fluid results in a decrease in pressure.
Correct Answer: B — Decrease in pressure
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Q. According to Bernoulli's principle, an increase in the speed of a fluid occurs simultaneously with a decrease in:
A.
Pressure
B.
Temperature
C.
Density
D.
Viscosity
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Solution
Bernoulli's principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure.
Correct Answer: A — Pressure
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Q. According to Bernoulli's principle, an increase in the speed of a fluid occurs simultaneously with a decrease in which of the following? (2019)
A.
Pressure
B.
Density
C.
Viscosity
D.
Temperature
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Solution
Bernoulli's principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure.
Correct Answer: A — Pressure
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