Physics
Q. A resistor of 10Ω is connected to a 20V battery. What is the power consumed by the resistor? (2021)
A.
40W
B.
20W
C.
10W
D.
2W
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Solution
Power (P) is given by P = V^2/R = (20V)^2 / 10Ω = 400/10 = 40W.
Correct Answer: A — 40W
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Q. A resistor of 10Ω is connected to a 20V power supply. What is the power consumed by the resistor? (2021)
A.
40W
B.
20W
C.
10W
D.
2W
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Solution
Power (P) is given by P = V^2/R = (20V)^2 / 10Ω = 400/10 = 40W.
Correct Answer: A — 40W
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Q. A rotating object has a moment of inertia I and an angular velocity ω. What is its rotational kinetic energy? (2020)
A.
(1/2)Iω
B.
(1/2)Iω²
C.
Iω²
D.
I/2ω²
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Solution
Rotational kinetic energy K.E. = (1/2)Iω².
Correct Answer: B — (1/2)Iω²
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Q. A rotating object has an angular momentum L. If its moment of inertia is halved and angular velocity is doubled, what is the new angular momentum? (2022)
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Solution
L = Iω, if I is halved and ω is doubled, L' = (1/2)(2ω) = L.
Correct Answer: B — 2L
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Q. A simple pendulum completes 20 oscillations in 40 seconds. What is its time period? (2021)
A.
1 s
B.
2 s
C.
0.5 s
D.
0.25 s
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Solution
Time period (T) = Total time / Number of oscillations = 40 s / 20 = 2 s.
Correct Answer: B — 2 s
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Q. A simple pendulum has a length of 1 m. What is its time period? (2023)
A.
1.0 s
B.
2.0 s
C.
0.5 s
D.
0.25 s
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Solution
The time period T of a simple pendulum is given by T = 2π√(L/g). For L = 1 m and g = 9.8 m/s², T = 2π√(1/9.8) ≈ 2.0 s.
Correct Answer: A — 1.0 s
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Q. A simple pendulum oscillates with a period of 2 seconds. What is the length of the pendulum? (2021)
A.
0.5 m
B.
1 m
C.
2 m
D.
4 m
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Solution
The period T of a simple pendulum is given by T = 2π√(L/g). Rearranging gives L = (T^2 * g) / (4π^2). Using g = 9.8 m/s² and T = 2 s, we find L = (2^2 * 9.8) / (4π^2) ≈ 1 m.
Correct Answer: B — 1 m
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Q. A solenoid produces a magnetic field similar to that of a bar magnet. What is the primary factor that determines the strength of the magnetic field in a solenoid? (2021)
A.
Length of the solenoid
B.
Number of turns per unit length
C.
Material of the solenoid
D.
Current flowing through the solenoid
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Solution
The strength of the magnetic field in a solenoid is primarily determined by the number of turns per unit length and the current flowing through it.
Correct Answer: B — Number of turns per unit length
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Q. A solid cylinder rolls down an incline. If its height is h, what is its linear speed at the bottom? (2023)
A.
√(gh)
B.
√(2gh)
C.
√(3gh)
D.
√(4gh)
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Solution
Using conservation of energy, potential energy converts to kinetic energy. For a solid cylinder, v = √(2gh).
Correct Answer: B — √(2gh)
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Q. A solid sphere of radius R rolls without slipping down an incline of height h. What is its speed at the bottom of the incline? (2021)
A.
√(2gh)
B.
√(3gh)
C.
√(4gh)
D.
√(5gh)
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Solution
Using conservation of energy, potential energy at the top = kinetic energy at the bottom. For a solid sphere, v = √(5gh/7). Thus, speed at the bottom is √(3gh).
Correct Answer: B — √(3gh)
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Q. A solid sphere of radius R rolls without slipping down an inclined plane of height h. What is the speed of the center of mass at the bottom of the incline? (2021)
A.
√(2gh)
B.
√(3gh)
C.
√(4gh)
D.
√(5gh)
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Solution
Using conservation of energy, potential energy at height h = kinetic energy at the bottom. For a solid sphere, v = √(3gh).
Correct Answer: B — √(3gh)
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Q. A sound wave travels at a speed of 340 m/s and has a frequency of 1700 Hz. What is its wavelength? (2021)
A.
0.2 m
B.
0.5 m
C.
2 m
D.
1 m
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Solution
Wavelength (λ) = Speed (v) / Frequency (f) = 340 m/s / 1700 Hz = 0.2 m.
Correct Answer: A — 0.2 m
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Q. A sound wave travels through air at 343 m/s. If its frequency is 686 Hz, what is its wavelength? (2023)
A.
0.5 m
B.
1 m
C.
2 m
D.
3 m
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Solution
Wavelength λ = v/f = 343 m/s / 686 Hz = 0.5 m.
Correct Answer: A — 0.5 m
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Q. A sound wave travels through air at a speed of 340 m/s. If the frequency of the sound is 170 Hz, what is the wavelength?
A.
1 m
B.
2 m
C.
3 m
D.
4 m
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Solution
The wavelength λ is given by λ = v/f. Thus, λ = 340/170 = 2 m.
Correct Answer: B — 2 m
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Q. A stone is thrown horizontally from a height of 45 m. How long will it take to hit the ground? (Take g = 10 m/s²) (2023)
A.
3 s
B.
4.5 s
C.
5 s
D.
6 s
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Solution
Using h = 0.5 * g * t^2, we have 45 = 0.5 * 10 * t^2. Solving gives t^2 = 9, so t = 3 s.
Correct Answer: A — 3 s
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Q. A train moving at 72 km/h applies brakes and comes to a stop in 5 seconds. What is the deceleration? (2023)
A.
2 m/s²
B.
3 m/s²
C.
4 m/s²
D.
5 m/s²
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Solution
First convert speed to m/s: 72 km/h = 20 m/s. Deceleration = (final velocity - initial velocity) / time = (0 - 20) / 5 = -4 m/s².
Correct Answer: C — 4 m/s²
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Q. A tuning fork produces a sound wave of frequency 440 Hz. What is the period of the wave? (2019)
A.
0.00227 s
B.
0.005 s
C.
0.01 s
D.
0.001 s
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Solution
Period T = 1/f = 1/440 Hz ≈ 0.00227 s.
Correct Answer: A — 0.00227 s
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Q. A tuning fork produces a sound wave of frequency 440 Hz. What is the time period of this sound wave? (2021)
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/f = 1/440 Hz ≈ 0.00227 s.
Correct Answer: A — 0.00227 s
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Q. A tuning fork produces a sound wave of frequency 440 Hz. What is the time period of the sound wave?
A.
0.00227 s
B.
0.005 s
C.
0.01 s
D.
0.02 s
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Solution
The time period T is the reciprocal of frequency f. Thus, T = 1/f = 1/440 ≈ 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 fork? (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/f = 1/440 Hz ≈ 0.00227 s.
Correct Answer: A — 0.00227 s
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Q. A uniform rod of length L is pivoted at one end and released from rest. What is the angular speed 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 converts to rotational kinetic energy. Angular speed ω = √(3g/L).
Correct Answer: B — √(2g/L)
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Q. A uniform rod of length L is pivoted at one end and released from rest. What is the angular speed when it reaches the vertical position? (2019)
A.
√(3g/L)
B.
√(2g/L)
C.
√(g/L)
D.
√(4g/L)
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Solution
Using conservation of energy, potential energy converts to rotational kinetic energy. Angular speed ω = √(3g/L).
Correct Answer: B — √(2g/L)
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Q. A vehicle travels with a uniform speed of 60 km/h. How far will it travel in 2 hours? (2023)
A.
80 km
B.
100 km
C.
120 km
D.
140 km
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Solution
Distance = speed * time = 60 km/h * 2 h = 120 km.
Correct Answer: C — 120 km
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Q. A wave has a frequency of 10 Hz and a wavelength of 5 m. What is its speed? (2020)
A.
50 m/s
B.
10 m/s
C.
2 m/s
D.
5 m/s
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Solution
Speed (v) = frequency (f) × wavelength (λ) = 10 Hz × 5 m = 50 m/s.
Correct Answer: A — 50 m/s
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Q. A wave has a frequency of 500 Hz and a wavelength of 0.6 m. What is the speed of the wave? (2022)
A.
300 m/s
B.
500 m/s
C.
600 m/s
D.
400 m/s
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Solution
Using the wave equation v = fλ, we find v = 500 Hz * 0.6 m = 300 m/s.
Correct Answer: A — 300 m/s
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Q. A wave has a frequency of 60 Hz and a wavelength of 3 m. What is its speed? (2016)
A.
180 m/s
B.
120 m/s
C.
60 m/s
D.
90 m/s
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Solution
Speed v = f × λ = 60 Hz × 3 m = 180 m/s.
Correct Answer: A — 180 m/s
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Q. A wave has a frequency of 60 Hz and a wavelength of 3 m. What is the speed of the wave?
A.
180 m/s
B.
120 m/s
C.
60 m/s
D.
30 m/s
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Solution
The speed v of a wave is given by v = fλ. Thus, v = 60 * 3 = 180 m/s.
Correct Answer: B — 120 m/s
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Q. A wave has a speed of 300 m/s and a frequency of 150 Hz. What is its wavelength? (2022)
A.
1 m
B.
2 m
C.
3 m
D.
4 m
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Solution
Wavelength λ can be calculated using the formula λ = v/f. Therefore, λ = 300 m/s / 150 Hz = 2 m.
Correct Answer: B — 2 m
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Q. A wave on a string has a speed of 50 m/s and a wavelength of 2 m. What is its frequency? (2018)
A.
25 Hz
B.
50 Hz
C.
100 Hz
D.
75 Hz
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Solution
Frequency f = v/λ = 50 m/s / 2 m = 25 Hz.
Correct Answer: A — 25 Hz
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Q. A wave on a string is described by the equation y(x, t) = 0.05 sin(2π(0.1x - 5t)). What is the amplitude of the wave?
A.
0.01 m
B.
0.05 m
C.
0.1 m
D.
0.2 m
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Solution
The amplitude of the wave is the coefficient in front of the sine function. Here, the amplitude is 0.05 m.
Correct Answer: B — 0.05 m
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