Q. If J = [[1, 2, 1], [0, 1, 3], [2, 1, 0]], calculate det(J). (2023)
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Solution
Using the determinant formula, det(J) = 1*(1*0 - 3*1) - 2*(0*0 - 3*2) + 1*(0*1 - 1*2) = 1*(-3) - 2*(-6) + 1*(-2) = -3 + 12 - 2 = 7.
Correct Answer: A — -4
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Q. If J = [[1, 2], [2, 4]], what is det(J)? (2022)
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Solution
Det(J) = (1*4) - (2*2) = 4 - 4 = 0.
Correct Answer: A — 0
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Q. If one root of the equation x² - 6x + k = 0 is 2, find k. (2022)
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Solution
Using the root 2 in the equation: 2² - 6*2 + k = 0, we find k = 10.
Correct Answer: B — 10
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Q. If one root of the equation x² - 7x + k = 0 is 3, find k. (2023)
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Solution
Using the root, substitute x = 3: 3² - 7*3 + k = 0, which gives k = 10.
Correct Answer: A — 10
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Q. If one root of the equation x² - 7x + k = 0 is 3, what is the value of k? (2020)
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Solution
Using the root, substitute x = 3: 3² - 7*3 + k = 0, which gives k = 9.
Correct Answer: D — 9
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Q. If one root of the equation x² - 7x + p = 0 is 3, what is the value of p? (2020)
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Solution
Using the root, substitute x = 3: 3² - 7*3 + p = 0, which gives p = 6.
Correct Answer: B — 9
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Q. If sin(θ) = 0.5, what is θ in degrees? (2014)
A.
30°
B.
45°
C.
60°
D.
90°
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Solution
sin(30°) = 0.5, so θ = 30°.
Correct Answer: A — 30°
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Q. If sin(θ) = 0.6, what is the approximate value of θ in degrees? (2019)
A.
36.87°
B.
45°
C.
53.13°
D.
60°
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Solution
Using inverse sine, θ ≈ 36.87°
Correct Answer: C — 53.13°
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Q. If sin(θ) = 0.8, what is cos(θ) using Pythagorean identity? (2020)
A.
0.6
B.
0.8
C.
0.4
D.
0.2
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Solution
Using sin²(θ) + cos²(θ) = 1, cos²(θ) = 1 - 0.64 = 0.36, cos(θ) = 0.6
Correct Answer: A — 0.6
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Q. If sin(θ) = 0.8, what is cos(θ)? (2022)
A.
0.6
B.
0.8
C.
0.4
D.
0.2
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Solution
Using sin²(θ) + cos²(θ) = 1, cos(θ) = √(1 - 0.8²) = √(0.36) = 0.6.
Correct Answer: A — 0.6
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Q. If sin(θ) = 0.866, what is θ in degrees? (2020)
A.
30°
B.
45°
C.
60°
D.
90°
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Solution
sin(60°) = √3/2 ≈ 0.866, so θ = 60°.
Correct Answer: C — 60°
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Q. If sin(θ) = 0.866, what is θ? (2022)
A.
30°
B.
45°
C.
60°
D.
90°
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Solution
sin(60°) = √3/2 ≈ 0.866, so θ = 60°.
Correct Answer: C — 60°
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Q. If sin(θ) = 1, what is the value of θ? (2023)
A.
0°
B.
90°
C.
180°
D.
270°
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Solution
sin(90°) = 1, so θ = 90°.
Correct Answer: B — 90°
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Q. If sin(θ) = 1, what is θ? (2023)
A.
0°
B.
30°
C.
90°
D.
180°
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Solution
sin(90°) = 1, so θ = 90°.
Correct Answer: C — 90°
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Q. If sin(θ) = 1/2, what is the possible value of θ? (2022)
A.
30°
B.
60°
C.
90°
D.
45°
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Solution
sin(30°) = 1/2, so θ = 30°.
Correct Answer: A — 30°
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Q. If sin(θ) = 1/√2, what is cos(θ)? (2022)
A.
1/√2
B.
0
C.
√2/2
D.
1
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Solution
Using sin²(θ) + cos²(θ) = 1, cos(θ) = √(1 - (1/√2)²) = √(1/2) = √2/2
Correct Answer: C — √2/2
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Q. If sin(θ) = 1/√2, what is θ in degrees?
A.
30°
B.
45°
C.
60°
D.
90°
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Solution
sin(45°) = 1/√2, so θ = 45°
Correct Answer: B — 45°
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Q. If tan(θ) = 1, what is the value of θ? (2020)
A.
0°
B.
30°
C.
45°
D.
60°
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Solution
tan(45°) = 1, so θ = 45°.
Correct Answer: C — 45°
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Q. If the amplitude of a wave is doubled, how does it affect the energy of the wave? (2020)
A.
Remains the same
B.
Doubles
C.
Increases by four times
D.
Halves
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Solution
Energy of a wave is proportional to the square of the amplitude. If amplitude is doubled, energy increases by (2^2) = 4 times.
Correct Answer: C — Increases by four times
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Q. If the amplitude of a wave is doubled, how does this affect the energy carried by the wave? (2021)
A.
Energy is halved
B.
Energy remains the same
C.
Energy is doubled
D.
Energy is quadrupled
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Solution
The energy carried by a wave is proportional to the square of the amplitude. Therefore, if the amplitude is doubled, the energy increases by a factor of four.
Correct Answer: D — Energy is quadrupled
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Q. If the area of a circle is 78.5 cm², what is the radius? (2021)
A.
5 cm
B.
7 cm
C.
10 cm
D.
6 cm
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Solution
Area = πr²; 78.5 = π * r²; r² = 78.5/π = 25; r = 5 cm.
Correct Answer: B — 7 cm
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Q. If the area of a coil is doubled while keeping the magnetic field constant, what happens to the magnetic flux through the coil? (2023)
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
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Solution
Magnetic flux (Φ) is given by the product of magnetic field (B) and area (A). If the area is doubled and the magnetic field remains constant, the magnetic flux also doubles.
Correct Answer: A — It doubles
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Q. If the capacitance in an AC circuit is increased, what happens to the capacitive reactance? (2023)
A.
It increases
B.
It decreases
C.
It remains the same
D.
It becomes zero
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Solution
Capacitive reactance XC = 1/(ωC). If capacitance C increases, XC decreases.
Correct Answer: B — It decreases
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Q. If the charge on a capacitor is doubled, what happens to the energy stored? (2019)
A.
It remains the same
B.
It doubles
C.
It quadruples
D.
It halves
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Solution
The energy stored in a capacitor is proportional to the square of the charge (U = Q^2/(2C)). Doubling the charge increases the energy by a factor of 4.
Correct Answer: C — It quadruples
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Q. If the circumference of a circle is 31.4 cm, what is its radius? (2022)
A.
5 cm
B.
10 cm
C.
15 cm
D.
20 cm
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Solution
Circumference = 2πr; 31.4 = 2 * π * r; r = 5 cm.
Correct Answer: A — 5 cm
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Q. If the circumference of a circle is 31.4 cm, what is its radius? (Use π = 3.14) (2015)
A.
5 cm
B.
7 cm
C.
10 cm
D.
8 cm
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Solution
Circumference = 2πr, so r = circumference / (2π) = 31.4 / (2 * 3.14) = 5 cm.
Correct Answer: A — 5 cm
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Q. If the circumference of a circle is 31.4 cm, what is the radius? (2020) 2020
A.
5 cm
B.
10 cm
C.
15 cm
D.
20 cm
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Solution
Circumference = 2πr. Therefore, r = Circumference / (2π) = 31.4 cm / (2 * 3.14) = 5 cm.
Correct Answer: A — 5 cm
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Q. If the concentration of a reactant is increased in a system at equilibrium, what will happen according to Le Chatelier's principle?
A.
The equilibrium will shift to the right.
B.
The equilibrium will shift to the left.
C.
The equilibrium will not change.
D.
The reaction will stop.
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Solution
According to Le Chatelier's principle, if a change is made to a system at equilibrium, the system will adjust to counteract that change. Increasing the concentration of a reactant will shift the equilibrium to the right, favoring the formation of products.
Correct Answer: A — The equilibrium will shift to the right.
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Q. If the concentration of a reactant is tripled in a second-order reaction, how does the rate change? (2023)
A.
Increases by 3 times
B.
Increases by 6 times
C.
Increases by 9 times
D.
Increases by 12 times
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Solution
For a second-order reaction, if concentration is tripled, the rate increases by 3² = 9 times.
Correct Answer: C — Increases by 9 times
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Q. If the concentration of Cu²⁺ in a cell is increased, what happens to the cell potential?
A.
Increases
B.
Decreases
C.
Remains the same
D.
Becomes zero
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Solution
Increasing the concentration of Cu²⁺ increases the cell potential according to the Nernst equation.
Correct Answer: A — Increases
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