Engineering Entrance
Q. In a harmonic oscillator, if the mass is doubled while keeping the spring constant the same, how does the frequency change? (2021)
A.
Increases
B.
Decreases
C.
Remains the same
D.
Becomes zero
Show solution
Solution
Frequency (f) = (1/2π)√(k/m). If mass (m) is doubled, frequency decreases.
Correct Answer: B — Decreases
Learn More →
Q. In a heat engine, if the input heat is 500 J and the work done is 300 J, what is the efficiency? (2023) 2023
A.
60%
B.
50%
C.
40%
D.
70%
Show solution
Solution
Efficiency (η) = Work done / Input heat = 300 J / 500 J = 0.6 or 60%.
Correct Answer: A — 60%
Learn More →
Q. In a lottery, there are 10 tickets, and 2 are winning tickets. What is the probability of picking a winning ticket?
A.
1/5
B.
1/10
C.
1/2
D.
2/10
Show solution
Solution
Probability = Number of winning tickets / Total tickets = 2/10 = 1/5.
Correct Answer: A — 1/5
Learn More →
Q. In a lottery, there are 10 tickets, and 3 are winning tickets. What is the probability of picking a winning ticket? (2022)
A.
1/3
B.
1/4
C.
1/5
D.
1/2
Show solution
Solution
Probability = Number of winning tickets / Total tickets = 3/10.
Correct Answer: A — 1/3
Learn More →
Q. In a parallel circuit with two resistors of 6Ω and 3Ω, what is the total resistance? (2019)
A.
2Ω
B.
4Ω
C.
1.5Ω
D.
9Ω
Show solution
Solution
Using the formula 1/R_eq = 1/R1 + 1/R2, we get 1/R_eq = 1/6 + 1/3 = 1/6 + 2/6 = 3/6, thus R_eq = 2Ω.
Correct Answer: B — 4Ω
Learn More →
Q. In a parallel RLC circuit, if R = 50 ohms, L = 0.2H, and C = 50μF, what is the total admittance? (2023)
A.
0.02 S
B.
0.04 S
C.
0.06 S
D.
0.08 S
Show solution
Solution
Y = 1/R + j(ωC - 1/ωL); calculate Y for given values.
Correct Answer: C — 0.06 S
Learn More →
Q. In a parallel RLC circuit, if R = 50Ω, L = 0.2 H, and C = 50μF, what is the quality factor Q? (2015)
Show solution
Solution
Quality factor Q = (1/R) * √(L/C) = (1/50) * √(0.2/50e-6) = 2.
Correct Answer: B — 2
Learn More →
Q. In a purely capacitive AC circuit, the current leads the voltage by how many degrees? (2022)
A.
0°
B.
90°
C.
180°
D.
270°
Show solution
Solution
In a purely capacitive circuit, the current leads the voltage by 90°.
Correct Answer: B — 90°
Learn More →
Q. In a purely capacitive AC circuit, the current leads the voltage by how much phase angle? (2023)
A.
0 degrees
B.
90 degrees
C.
180 degrees
D.
270 degrees
Show solution
Solution
In a purely capacitive circuit, the current leads the voltage by 90 degrees.
Correct Answer: B — 90 degrees
Learn More →
Q. In a reaction A → B, if the concentration of A decreases from 0.8 M to 0.4 M in 20 minutes, what is the average rate of reaction? (2019)
A.
0.02 M/min
B.
0.04 M/min
C.
0.1 M/min
D.
0.05 M/min
Show solution
Solution
Average rate = Δ[A]/Δt = (0.8 - 0.4) / 20 = 0.02 M/min.
Correct Answer: D — 0.05 M/min
Learn More →
Q. In a reaction, if the concentration of reactant A is halved, and the rate constant remains the same, how does the rate change for a first-order reaction? (2021)
A.
Doubles
B.
Halves
C.
Remains the same
D.
Quadruples
Show solution
Solution
For a first-order reaction, if [A] is halved, the rate also halves.
Correct Answer: B — Halves
Learn More →
Q. In a reaction, if the concentration of reactant A is halved, and the rate of reaction decreases to one-fourth, what is the order of the reaction? (2020)
A.
Zero
B.
First
C.
Second
D.
Third
Show solution
Solution
If the rate decreases to one-fourth when concentration is halved, the reaction is second-order.
Correct Answer: C — Second
Learn More →
Q. In a reversible reaction, if the concentration of products increases, what happens to the rate of the forward reaction? (2021)
A.
It increases
B.
It decreases
C.
It remains constant
D.
It becomes zero
Show solution
Solution
According to Le Chatelier's principle, if the concentration of products increases, the system will shift to the left, decreasing the rate of the forward reaction.
Correct Answer: B — It decreases
Learn More →
Q. In a reversible reaction, if the concentration of products increases, what happens to the equilibrium position? (2021)
A.
It shifts to the left
B.
It shifts to the right
C.
It remains unchanged
D.
It shifts to the center
Show solution
Solution
According to Le Chatelier's principle, if the concentration of products increases, the equilibrium will shift to the left to counteract the change.
Correct Answer: A — It shifts to the left
Learn More →
Q. In a reversible reaction, if the concentration of products increases, what happens to the equilibrium position? (2021) 2021
A.
It shifts to the left
B.
It shifts to the right
C.
It remains unchanged
D.
It shifts to the center
Show solution
Solution
According to Le Chatelier's principle, if the concentration of products increases, the equilibrium will shift to the left to counteract the change.
Correct Answer: A — It shifts to the left
Learn More →
Q. In a reversible reaction, if the concentration of reactants is increased, what will happen to the position of equilibrium? (2021)
A.
It will shift to the right
B.
It will shift to the left
C.
It will remain unchanged
D.
It will shift to the center
Show solution
Solution
According to Le Chatelier's principle, increasing the concentration of reactants will shift the equilibrium position to the right to favor the formation of products.
Correct Answer: A — It will shift to the right
Learn More →
Q. In a reversible reaction, if the concentration of reactants is increased, what will happen to the equilibrium position? (2021)
A.
It will shift to the right
B.
It will shift to the left
C.
It will remain unchanged
D.
It will shift to the center
Show solution
Solution
According to Le Chatelier's principle, if the concentration of reactants is increased, the equilibrium will shift to the right to favor the formation of products.
Correct Answer: A — It will shift to the right
Learn More →
Q. In a second-order reaction, if the initial concentration is 0.1 M and the rate constant is 0.05 M⁻¹s⁻¹, what is the time taken to reach half the initial concentration? (2020)
A.
10 s
B.
20 s
C.
5 s
D.
15 s
Show solution
Solution
For a second-order reaction, t₁/₂ = 1 / (k[A₀]) = 1 / (0.05 * 0.1) = 200 s.
Correct Answer: B — 20 s
Learn More →
Q. In a series RLC circuit, if R = 10 ohms, L = 0.1H, and C = 100μF, what is the resonant frequency? (2021)
A.
159.15 Hz
B.
100 Hz
C.
50 Hz
D.
200 Hz
Show solution
Solution
f0 = 1 / (2π√(LC)) = 1 / (2π√(0.1 × 100 × 10^-6)) = 159.15 Hz.
Correct Answer: A — 159.15 Hz
Learn More →
Q. In a series RLC circuit, if R = 20Ω, L = 0.1 H, and C = 100μF, what is the resonant frequency? (2020)
A.
50 Hz
B.
100 Hz
C.
159.15 Hz
D.
200 Hz
Show solution
Solution
Resonant frequency f₀ = 1 / (2π√(LC)) = 1 / (2π√(0.1 * 100e-6)) = 159.15 Hz.
Correct Answer: C — 159.15 Hz
Learn More →
Q. In a series RLC circuit, if the inductive reactance is greater than the capacitive reactance, the circuit is said to be: (2019)
A.
Resonant
B.
Capacitive
C.
Inductive
D.
Purely resistive
Show solution
Solution
If inductive reactance (XL) is greater than capacitive reactance (XC), the circuit is inductive.
Correct Answer: C — Inductive
Learn More →
Q. In a series RLC circuit, if the resistance is 10 ohms, inductance is 0.1 H, and capacitance is 100 μF, what is the resonant frequency? (2021)
A.
50 Hz
B.
100 Hz
C.
159 Hz
D.
200 Hz
Show solution
Solution
Resonant frequency f = 1/(2π√(LC)) = 1/(2π√(0.1 * 100e-6)) = 159.15 Hz.
Correct Answer: C — 159 Hz
Learn More →
Q. In a series RLC circuit, if the resistance is 10Ω, inductance is 0.1H, and capacitance is 100μF, what is the resonant frequency? (2021)
A.
50Hz
B.
100Hz
C.
159Hz
D.
200Hz
Show solution
Solution
Resonant frequency f0 = 1/(2π√(LC)) = 1/(2π√(0.1*100e-6)) ≈ 159Hz.
Correct Answer: C — 159Hz
Learn More →
Q. In a thin film interference experiment, what type of interference occurs when light reflects off a denser medium? (2023)
A.
Constructive interference
B.
Destructive interference
C.
No interference
D.
Total internal reflection
Show solution
Solution
When light reflects off a denser medium, a phase change of π occurs, leading to destructive interference for certain path differences.
Correct Answer: B — Destructive interference
Learn More →
Q. In a zero-order reaction, the rate of reaction is independent of the concentration of the reactants. What is the unit of the rate constant (k) for a zero-order reaction? (2023)
A.
mol/L·s
B.
L^2/mol·s
C.
mol/L
D.
s^-1
Show solution
Solution
For a zero-order reaction, the rate is constant and does not depend on the concentration of reactants. The unit of the rate constant (k) is mol/L·s.
Correct Answer: A — mol/L·s
Learn More →
Q. In a zero-order reaction, the rate of reaction is independent of which of the following? (2023) 2023
A.
Concentration of reactants
B.
Temperature
C.
Presence of a catalyst
D.
All of the above
Show solution
Solution
In a zero-order reaction, the rate is constant and does not depend on the concentration of the reactants.
Correct Answer: A — Concentration of reactants
Learn More →
Q. In an AC circuit, if the frequency is 60Hz and the inductance is 0.2H, what is the inductive reactance? (2021)
A.
12.56Ω
B.
37.68Ω
C.
75.36Ω
D.
100Ω
Show solution
Solution
Inductive reactance (XL) = 2πfL = 2π(60)(0.2) ≈ 75.36Ω.
Correct Answer: B — 37.68Ω
Learn More →
Q. In an AC circuit, if the power factor is 0.8, what is the angle between the voltage and current? (2020)
A.
36.87°
B.
53.13°
C.
60°
D.
45°
Show solution
Solution
The angle θ can be found using cos(θ) = power factor. Therefore, θ = cos⁻¹(0.8) ≈ 36.87°.
Correct Answer: B — 53.13°
Learn More →
Q. In an AC circuit, if the resistance is 10 ohms and the inductive reactance is 20 ohms, what is the impedance? (2020)
A.
10 ohms
B.
20 ohms
C.
√(10² + 20²)
D.
30 ohms
Show solution
Solution
The impedance Z = √(R² + XL²) = √(10² + 20²) = √(100 + 400) = √500 = 22.36 ohms.
Correct Answer: C — √(10² + 20²)
Learn More →
Q. In an AC circuit, if the voltage is 120 V and the current is 10 A with a power factor of 0.8, what is the real power consumed? (2021)
A.
960 W
B.
1200 W
C.
800 W
D.
1000 W
Show solution
Solution
Real power P = V * I * power factor = 120 * 10 * 0.8 = 960 W.
Correct Answer: A — 960 W
Learn More →
Showing 571 to 600 of 1443 (49 Pages)