Q. If the electric field at a point is 1000 N/C and the charge at that point is 5 µC, what is the force experienced by the charge?
A.
0.005 N
B.
0.05 N
C.
0.5 N
D.
5 N
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Solution
F = E * q = 1000 N/C * 5 × 10^-6 C = 0.005 N.
Correct Answer:
B
— 0.05 N
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Q. If the frequency of a vibrating tuning fork is 440 Hz, what is the time period of the vibration? (2023)
A.
0.00227 s
B.
0.005 s
C.
0.01 s
D.
0.0227 s
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Solution
The time period T is the reciprocal of frequency f, T = 1/f. Therefore, T = 1/440 ≈ 0.00227 s.
Correct Answer:
A
— 0.00227 s
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Q. If the frequency of a wave is doubled, what happens to its wavelength, assuming the speed remains constant? (2021)
A.
Doubles
B.
Halves
C.
Remains the same
D.
Quadruples
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Solution
Wavelength (λ) is inversely proportional to frequency (f) when speed (v) is constant: λ = v/f. If f is doubled, λ is halved.
Correct Answer:
B
— Halves
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Q. If the frequency of a wave is halved, what happens to its wavelength? (2015)
A.
Halves
B.
Doubles
C.
Remains the same
D.
Increases by four times
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Solution
Wavelength is inversely proportional to frequency. If frequency is halved, wavelength doubles.
Correct Answer:
B
— Doubles
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Q. If the frequency of an AC source is doubled, how does the inductive reactance change? (2020)
A.
Doubles
B.
Halves
C.
Remains the same
D.
Quadruples
Show solution
Solution
Xl = 2πfL; if f is doubled, Xl also doubles.
Correct Answer:
B
— Halves
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Q. If the frequency of an AC source is doubled, what happens to the inductive reactance? (2014)
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
Show solution
Solution
Inductive reactance XL = 2πfL, so if frequency f is doubled, XL halves.
Correct Answer:
B
— It halves
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Q. If the frequency of an AC source is doubled, what happens to the inductive reactance of an inductor? (2021)
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
Show solution
Solution
Inductive reactance Xl = ωL, so if frequency is doubled, Xl halves.
Correct Answer:
B
— It halves
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Q. If the frequency of an AC source is doubled, what happens to the reactance of a capacitor? (2023)
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
Show solution
Solution
The capacitive reactance Xc = 1/(2πfC) halves when the frequency f is doubled.
Correct Answer:
B
— It halves
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Q. If the frequency of an AC source is doubled, what happens to the reactance of an inductor? (2023)
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
Show solution
Solution
The reactance of an inductor is given by XL = ωL. If frequency is doubled, reactance also doubles.
Correct Answer:
A
— It doubles
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Q. If the gravitational force between two objects is 20 N and the distance between them is doubled, what will be the new force?
A.
5 N
B.
10 N
C.
20 N
D.
40 N
Show solution
Solution
F is inversely proportional to r². If r is doubled, F becomes F/4 = 20 N / 4 = 5 N.
Correct Answer:
A
— 5 N
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Q. If the inductance of a coil is 0.5H and the frequency is 60Hz, what is the inductive reactance? (2023)
A.
31.42 ohms
B.
18.85 ohms
C.
37.70 ohms
D.
25.13 ohms
Show solution
Solution
Xl = 2πfL = 2π × 60 × 0.5 = 31.42 ohms.
Correct Answer:
A
— 31.42 ohms
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Q. If the inductive reactance of a coil is 30Ω and the resistance is 10Ω, what is the total impedance? (2018)
A.
10Ω
B.
30Ω
C.
33.33Ω
D.
40Ω
Show solution
Solution
Total impedance Z = √(R² + (XL)²) = √(10² + 30²) = √(100 + 900) = √1000 = 31.62Ω.
Correct Answer:
C
— 33.33Ω
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Q. If the latent heat of fusion of ice is 334 J/g, how much heat is required to melt 50 g of ice? (2019)
A.
1670 J
B.
3340 J
C.
5000 J
D.
1000 J
Show solution
Solution
Heat required = mass × latent heat = 50 g × 334 J/g = 16700 J.
Correct Answer:
A
— 1670 J
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Q. If the latent heat of vaporization of water is 2260 kJ/kg, how much energy is required to convert 0.5 kg of water at 100°C to steam at 100°C?
A.
1130 kJ
B.
2260 kJ
C.
3390 kJ
D.
4520 kJ
Show solution
Solution
Energy required = mass * latent heat = 0.5 kg * 2260 kJ/kg = 1130 kJ.
Correct Answer:
A
— 1130 kJ
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Q. If the magnetic field strength is doubled, what happens to the force experienced by a current-carrying conductor in that field? (2022)
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
Show solution
Solution
The force experienced by a current-carrying conductor in a magnetic field is directly proportional to the magnetic field strength. Therefore, if the magnetic field strength is doubled, the force also doubles.
Correct Answer:
A
— It doubles
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Q. If the magnetic field strength is doubled, what happens to the force experienced by a current-carrying conductor? (2022)
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
Show solution
Solution
The force experienced by a current-carrying conductor in a magnetic field is directly proportional to the magnetic field strength. Therefore, if the magnetic field strength is doubled, the force also doubles.
Correct Answer:
A
— It doubles
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Q. If the magnetic field strength is doubled, what happens to the force on a current-carrying conductor in that field? (2022)
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
Show solution
Solution
The force on a current-carrying conductor is directly proportional to the magnetic field strength, so if the field strength is doubled, the force also doubles.
Correct Answer:
A
— It doubles
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Q. If the magnetic field strength is doubled, what happens to the force on a current-carrying conductor? (2022)
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
Show solution
Solution
The force on a current-carrying conductor is directly proportional to the magnetic field strength, so if the magnetic field strength is doubled, the force also doubles.
Correct Answer:
A
— It doubles
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Q. If the magnetic flux through a coil changes from 0.2 Wb to 0.5 Wb in 2 seconds, what is the average induced EMF in the coil? (2021)
A.
150 V
B.
100 V
C.
75 V
D.
50 V
Show solution
Solution
Average induced EMF (ε) = -ΔΦ/Δt = -(0.5 Wb - 0.2 Wb) / 2 s = -0.3 Wb / 2 s = -0.15 V. The absolute value is 0.15 V or 150 mV.
Correct Answer:
B
— 100 V
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Q. If the magnetic flux through a coil changes from 0.2 Wb to 0.5 Wb in 2 seconds, what is the average induced EMF? (2021)
A.
150 V
B.
100 V
C.
75 V
D.
50 V
Show solution
Solution
Average induced EMF = -ΔΦ/Δt = -(0.5 Wb - 0.2 Wb) / 2 s = -0.15 Wb/s = 150 V.
Correct Answer:
B
— 100 V
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Q. If the mass of an object is measured in kilograms and its volume in cubic meters, what is the unit of density? (2022)
A.
kg/m
B.
kg/m^3
C.
m^3/kg
D.
m/kg
Show solution
Solution
Density is defined as mass per unit volume, so the unit of density is kg/m³.
Correct Answer:
B
— kg/m^3
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Q. If the mass of an object is tripled and the distance from the center of the Earth is halved, how does the gravitational force change?
A.
It triples
B.
It increases by a factor of 6
C.
It increases by a factor of 9
D.
It decreases
Show solution
Solution
F ∝ m/r²; if m is tripled and r is halved, F = 3m/(1/4) = 12m, so it increases by a factor of 9.
Correct Answer:
C
— It increases by a factor of 9
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Q. If the mass of the Earth were to double, what would happen to the gravitational force experienced by an object on its surface?
A.
It doubles
B.
It halves
C.
It quadruples
D.
It remains the same
Show solution
Solution
Gravitational force is directly proportional to mass. If mass doubles, force also doubles.
Correct Answer:
A
— It doubles
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Q. If the power factor of an AC circuit is 0.8, what is the angle between the current and voltage? (2021)
A.
36.87°
B.
53.13°
C.
60°
D.
45°
Show solution
Solution
The angle θ can be found using cos(θ) = power factor. Thus, θ = cos⁻¹(0.8) ≈ 36.87°.
Correct Answer:
B
— 53.13°
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Q. If the pressure of a gas is increased while keeping the temperature constant, what happens to its volume? (2020)
A.
It increases
B.
It decreases
C.
It remains the same
D.
It becomes zero
Show solution
Solution
According to Boyle's Law, P * V = constant at constant temperature, so if P increases, V must decrease.
Correct Answer:
B
— It decreases
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Q. If the radius of the Earth is doubled, what will happen to the gravitational force experienced by an object on its surface?
A.
It will double
B.
It will remain the same
C.
It will be halved
D.
It will be quartered
Show solution
Solution
Gravitational force is inversely proportional to the square of the radius. If radius is doubled, F becomes F/4.
Correct Answer:
D
— It will be quartered
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Q. If the radius of the Earth were to increase by 50%, what would happen to the weight of an object on its surface?
A.
It increases by 50%
B.
It increases by 25%
C.
It decreases by 25%
D.
It remains the same
Show solution
Solution
Weight is inversely proportional to the square of the radius. If radius increases by 50%, weight decreases by 25%.
Correct Answer:
C
— It decreases by 25%
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Q. If the radius of the Earth were to increase while keeping its mass constant, what would happen to the gravitational acceleration at its surface?
A.
It increases
B.
It decreases
C.
It remains the same
D.
It becomes zero
Show solution
Solution
Gravitational acceleration g = GM/R². If R increases, g decreases.
Correct Answer:
B
— It decreases
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Q. If the radius of the Earth were to increase while keeping its mass constant, what would happen to the gravitational acceleration at the surface? (2023)
A.
It increases
B.
It decreases
C.
It remains the same
D.
It becomes zero
Show solution
Solution
Gravitational acceleration is inversely proportional to the square of the radius. If radius increases, g decreases.
Correct Answer:
B
— It decreases
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Q. If the radius of the Earth were to increase while keeping its mass constant, what would happen to the value of g? (2023)
A.
g increases
B.
g decreases
C.
g remains the same
D.
g becomes zero
Show solution
Solution
If the radius increases while mass remains constant, g decreases because g = G * M / r^2.
Correct Answer:
B
— g decreases
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