Q. In a chemical reaction, what does the term 'activation energy' refer to? (2023)
A.
Energy released during the reaction
B.
Energy required to initiate the reaction
C.
Energy needed to maintain the reaction
D.
Energy that is lost
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Solution
Activation energy is the minimum energy required to initiate a chemical reaction.
Correct Answer:
B
— Energy required to initiate the reaction
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Q. In a chess tournament, each player plays against every other player exactly once. If there are 12 players, how many games are played?
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Solution
The number of games played is given by n(n-1)/2. For 12 players, it is 12(12-1)/2 = 66 games.
Correct Answer:
A
— 66
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Q. In a chess tournament, each player plays every other player exactly once. If there are 10 players, how many games are played?
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Solution
The number of games played is given by n(n-1)/2. For 10 players, it is 10(10-1)/2 = 45.
Correct Answer:
A
— 45
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Q. In a chess tournament, each player plays every other player once. If there are 12 players, how many games are played?
Show solution
Solution
The number of games played is given by n(n-1)/2. For 12 players, it is 12(12-1)/2 = 66 games.
Correct Answer:
A
— 66
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Q. In a chess tournament, if each player plays against every other player exactly once, and there are 10 players, how many games are played?
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Solution
The number of games played is given by the combination formula n(n-1)/2. For 10 players, it is 10(10-1)/2 = 45 games.
Correct Answer:
A
— 45
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Q. In a circle, if a central angle measures 80 degrees, what is the measure of the inscribed angle that subtends the same arc?
A.
20 degrees
B.
40 degrees
C.
80 degrees
D.
160 degrees
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Solution
The inscribed angle is half the measure of the central angle that subtends the same arc. Therefore, the inscribed angle measures 80/2 = 40 degrees.
Correct Answer:
B
— 40 degrees
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Q. In a circle, if a chord is 12 cm long and the distance from the center to the chord is 5 cm, what is the radius of the circle?
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Solution
Using the formula: radius² = (distance from center to chord)² + (half of chord length)². Here, radius² = 5² + (12/2)² = 25 + 36 = 61, so radius = √61, which is approximately 7.81.
Correct Answer:
C
— 13
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Q. In a circle, if a chord is 12 units long and the distance from the center to the chord is 5 units, what is the radius of the circle?
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Solution
Using the formula: radius² = (distance from center to chord)² + (half of chord length)². Thus, radius² = 5² + (12/2)² = 25 + 36 = 61, so radius = √61 ≈ 7.81.
Correct Answer:
C
— 13
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Q. In a circle, if a chord is bisected by a radius at a right angle, and the radius is 9 cm, what is the length of the chord?
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Solution
Using the formula: chord length = 2√(radius² - (half of chord length)²). Here, half of chord length = √(9² - 0) = 9, so chord length = 2 * 9 = 18.
Correct Answer:
C
— 18
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Q. In a circle, if a chord is drawn, which of the following statements is true regarding the angles formed?
A.
The angles subtended by the chord at the center are equal.
B.
The angles subtended by the chord at the circumference are equal.
C.
The angles subtended at the center are half of those at the circumference.
D.
The angles subtended at the circumference are equal to those at the center.
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Solution
The angles subtended by the same chord at the circumference are equal.
Correct Answer:
B
— The angles subtended by the chord at the circumference are equal.
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Q. In a circle, if a chord is perpendicular to a radius at its endpoint, what can be inferred about the chord?
A.
It is the longest chord.
B.
It bisects the circle.
C.
It is a diameter.
D.
It is bisected by the radius.
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Solution
A radius that is perpendicular to a chord at its endpoint bisects the chord.
Correct Answer:
D
— It is bisected by the radius.
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Q. In a circle, if a tangent and a chord intersect at a point on the circle, and the angle between them is 30°, what is the angle subtended by the chord at the center?
A.
30°
B.
60°
C.
90°
D.
120°
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Solution
The angle subtended by the chord at the center is twice the angle between the tangent and the chord, so it is 2 * 30° = 60°.
Correct Answer:
B
— 60°
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Q. In a circle, if an angle subtended by an arc at the center is 80 degrees, what is the angle subtended by the same arc at any point on the circumference?
A.
20 degrees
B.
40 degrees
C.
80 degrees
D.
160 degrees
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Solution
The angle subtended at the circumference is half the angle subtended at the center. Therefore, the angle at the circumference is 80/2 = 40 degrees.
Correct Answer:
B
— 40 degrees
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Q. In a circle, if an angle subtended by an arc at the center is 80 degrees, what is the angle subtended by the same arc at any point on the remaining part of the circle? (2023)
A.
40 degrees
B.
80 degrees
C.
60 degrees
D.
20 degrees
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Solution
The angle subtended at the circumference is half the angle subtended at the center. Therefore, it is 80/2 = 40 degrees.
Correct Answer:
A
— 40 degrees
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Q. In a circle, if the angle subtended by a chord at the center is 80 degrees, what is the angle subtended at any point on the remaining part of the circle?
A.
40
B.
80
C.
100
D.
160
Show solution
Solution
The angle subtended at the circumference is half of that at the center, so it is 80/2 = 40 degrees.
Correct Answer:
A
— 40
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Q. In a circle, if the angle subtended by an arc at the center is 60 degrees, what is the angle subtended at any point on the remaining part of the circle?
A.
30 degrees
B.
60 degrees
C.
90 degrees
D.
120 degrees
Show solution
Solution
The angle subtended at the circumference is half of that at the center, so it is 30 degrees.
Correct Answer:
A
— 30 degrees
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Q. In a circle, if the angle subtended by an arc at the center is 60 degrees, what is the angle subtended at any point on the circumference?
A.
30 degrees
B.
60 degrees
C.
90 degrees
D.
120 degrees
Show solution
Solution
The angle subtended at the circumference is half of that at the center, so it is 30 degrees.
Correct Answer:
A
— 30 degrees
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Q. In a circle, if the length of an arc is 10 cm and the radius is 5 cm, what is the angle in radians subtended by the arc at the center? (2021)
A.
1 rad
B.
2 rad
C.
3 rad
D.
4 rad
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Solution
The angle in radians is given by the formula θ = s/r, where s is the arc length. Thus, θ = 10/5 = 2 rad.
Correct Answer:
B
— 2 rad
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Q. In a circle, if the radius is 10 units and a chord is 8 units long, what is the distance from the center of the circle to the chord?
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Solution
Using the formula: distance = √(radius² - (chord length/2)²) = √(10² - (8/2)²) = √(100 - 16) = √84 ≈ 9.17.
Correct Answer:
A
— 6
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Q. In a circle, if the radius is 5 cm and a chord is 6 cm long, what is the distance from the center of the circle to the chord?
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Solution
Using the formula d = √(r^2 - (c/2)^2), where r = 5 and c = 6, we get d = √(5^2 - 3^2) = √(25 - 9) = √16 = 4.
Correct Answer:
B
— 3
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Q. In a circle, if the radius is 5 cm and a chord is 8 cm long, what is the distance from the center of the circle to the chord?
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Solution
Using the formula d = √(r^2 - (c/2)^2): d = √(5^2 - (8/2)^2) = √(25 - 16) = √9 = 3.
Correct Answer:
B
— 4
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Q. In a circle, if the radius is 8 cm and a chord is 12 cm long, what is the distance from the center of the circle to the chord?
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Solution
Using the formula d = √(r² - (c/2)²): d = √(8² - (12/2)²) = √(64 - 36) = √28 ≈ 5.29.
Correct Answer:
C
— 6
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Q. In a circle, if the radius is doubled, how does the area change?
A.
It remains the same.
B.
It doubles.
C.
It quadruples.
D.
It increases by a factor of eight.
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Solution
If the radius is doubled, the area increases by a factor of four (since area is proportional to the square of the radius).
Correct Answer:
C
— It quadruples.
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Q. In a circle, if the radius is increased by 50%, what happens to the area of the circle?
A.
It increases by 50%
B.
It doubles
C.
It increases by 125%
D.
It increases by 75%
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Solution
If the radius increases by 50%, the new radius is 1.5r. The area becomes π(1.5r)² = 2.25πr², which is an increase of 125%.
Correct Answer:
C
— It increases by 125%
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Q. In a circle, if the radius is increased by 50%, what happens to the area?
A.
Increases by 25%
B.
Increases by 50%
C.
Increases by 75%
D.
Increases by 125%
Show solution
Solution
If the radius increases by 50%, the new radius is 1.5r. The area becomes π(1.5r)² = 2.25πr², which is an increase of 125%.
Correct Answer:
D
— Increases by 125%
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Q. In a circle, if two chords intersect at a point inside the circle, what is the relationship between the segments of the chords?
A.
They are equal
B.
They are proportional
C.
They are perpendicular
D.
They are parallel
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Solution
The segments of the chords are proportional to each other according to the intersecting chords theorem.
Correct Answer:
B
— They are proportional
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Q. In a circuit with a 10V battery and two resistors (3Ω and 6Ω) in series, what is the voltage drop across the 6Ω resistor?
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Solution
Voltage drop across R2 = (R2 / (R1 + R2)) * Vtotal = (6 / (3 + 6)) * 10 = 6.67V.
Correct Answer:
C
— 6V
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Q. In a circuit with a 10V battery and two resistors in parallel (4Ω and 6Ω), what is the voltage across each resistor?
A.
10V for both
B.
5V for both
C.
10V for 4Ω and 6V for 6Ω
D.
10V for 6Ω and 4V for 4Ω
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Solution
In a parallel circuit, the voltage across each resistor is the same as the source voltage. Therefore, both resistors have 10V across them.
Correct Answer:
A
— 10V for both
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Q. In a circuit with a 10V battery and two resistors in series (2Ω and 3Ω), what is the voltage drop across the 3Ω resistor?
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Solution
Using the voltage divider rule, V3 = (R3 / (R2 + R3)) * Vtotal = (3 / (2 + 3)) * 10 = 6V.
Correct Answer:
B
— 6V
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Q. In a circuit with a 10V battery and two resistors in series (R1 = 2Ω, R2 = 3Ω), what is the current flowing through the circuit?
A.
2A
B.
1A
C.
0.5A
D.
3A
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Solution
Total resistance R_total = R1 + R2 = 2Ω + 3Ω = 5Ω. Current I = V / R_total = 10V / 5Ω = 2A.
Correct Answer:
B
— 1A
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