Physics
Q. How much heat is required to raise the temperature of 500 g of water from 25°C to 75°C? (2020)
A.
10000 J
B.
5000 J
C.
20000 J
D.
15000 J
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Solution
Q = mcΔT = 500 g * 4.2 J/g°C * (75 - 25)°C = 10000 J.
Correct Answer: D — 15000 J
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Q. How much work is done when a force of 10 N moves an object 5 m in the direction of the force?
A.
25 J
B.
50 J
C.
75 J
D.
100 J
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Solution
Work = Force * Distance = 10 N * 5 m = 50 J.
Correct Answer: B — 50 J
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Q. How much work is done when a force of 30 N moves an object 4 m in the direction of the force?
A.
120 J
B.
90 J
C.
60 J
D.
30 J
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Solution
Work = Force * Distance = 30 N * 4 m = 120 J.
Correct Answer: A — 120 J
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Q. If 1 kg of water is heated from 25°C to 75°C, how much heat is absorbed? (Specific heat of water = 4.2 J/g°C) (2021)
A.
21000 J
B.
42000 J
C.
84000 J
D.
105000 J
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Solution
Q = mcΔT = (1000 g)(4.2 J/g°C)(50°C) = 210000 J.
Correct Answer: B — 42000 J
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Q. If 1000 J of heat is added to a gas and it expands doing 400 J of work, what is the change in internal energy? (2023)
A.
600 J
B.
400 J
C.
1000 J
D.
200 J
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Solution
Using the first law of thermodynamics: ΔU = Q - W = 1000 J - 400 J = 600 J.
Correct Answer: A — 600 J
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Q. If 1000 J of heat is added to a system and it does 400 J of work, what is the change in internal energy? (2021)
A.
600 J
B.
400 J
C.
1000 J
D.
1400 J
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Solution
Using the first law of thermodynamics, ΔU = Q - W = 1000 J - 400 J = 600 J.
Correct Answer: A — 600 J
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Q. If 200 g of water at 80°C is mixed with 300 g of water at 20°C, what will be the final temperature of the mixture? (Assume no heat loss to the surroundings)
A.
30°C
B.
40°C
C.
50°C
D.
60°C
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Solution
Using the formula m1c1T1 + m2c2T2 = (m1 + m2)cTfinal, we find Tfinal = 40°C.
Correct Answer: B — 40°C
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Q. If 2000 J of heat is added to a system and 500 J of work is done by the system, what is the change in internal energy of the system? (2021)
A.
1500 J
B.
2000 J
C.
2500 J
D.
3000 J
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Solution
Using the first law of thermodynamics: ΔU = Q - W = 2000 J - 500 J = 1500 J.
Correct Answer: A — 1500 J
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Q. If 500 J of heat is added to a system and 200 J of work is done by the system, what is the change in internal energy of the system?
A.
300 J
B.
500 J
C.
700 J
D.
200 J
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Solution
According to the first law of thermodynamics, ΔU = Q - W. Here, ΔU = 500 J - 200 J = 300 J.
Correct Answer: A — 300 J
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Q. If 500 J of heat is added to a system and it does 200 J of work, what is the change in internal energy? (2022)
A.
300 J
B.
200 J
C.
500 J
D.
700 J
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Solution
According to the first law of thermodynamics, ΔU = Q - W. Here, ΔU = 500 J - 200 J = 300 J.
Correct Answer: A — 300 J
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Q. If a 10 kg object is dropped from a height of 20 m, what is the velocity just before it hits the ground? (Assume g = 10 m/s²) (2019)
A.
10 m/s
B.
20 m/s
C.
14 m/s
D.
15 m/s
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Solution
Using v² = u² + 2gh, v = √(0 + 2 × 10 m/s² × 20 m) = √400 = 20 m/s.
Correct Answer: B — 20 m/s
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Q. If a 10 kg object is raised to a height of 5 m, what is the work done against gravity? (g = 9.8 m/s²)
A.
490 J
B.
980 J
C.
150 J
D.
250 J
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Solution
Work = m * g * h = 10 kg * 9.8 m/s² * 5 m = 490 J.
Correct Answer: B — 980 J
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Q. If a 10 N force is applied at an angle of 60 degrees to the horizontal while moving an object 3 m, what is the work done? (2020)
A.
15 J
B.
30 J
C.
25 J
D.
5 J
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Solution
Work done = Force × Distance × cos(θ) = 10 N × 3 m × cos(60°) = 10 N × 3 m × 0.5 = 15 J
Correct Answer: A — 15 J
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Q. If a 1000 kg car is moving at a speed of 15 m/s, what is its kinetic energy?
A.
112,500 J
B.
225,000 J
C.
150,000 J
D.
75,000 J
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Solution
Kinetic Energy = 0.5 × mass × velocity² = 0.5 × 1000 kg × (15 m/s)² = 112,500 J
Correct Answer: B — 225,000 J
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Q. If a 1000 kg car is moving with a speed of 15 m/s, what is its kinetic energy?
A.
112,500 J
B.
225,000 J
C.
75,000 J
D.
150,000 J
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Solution
Kinetic Energy = 0.5 × mass × velocity² = 0.5 × 1000 kg × (15 m/s)² = 112,500 J
Correct Answer: B — 225,000 J
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Q. If a 10Ω resistor is connected in parallel with a 5Ω resistor, what is the equivalent resistance? (2022)
A.
3.33Ω
B.
5Ω
C.
7.5Ω
D.
15Ω
Show solution
Solution
For parallel resistors, 1/R_eq = 1/R1 + 1/R2 = 1/10 + 1/5 = 1/10 + 2/10 = 3/10. Therefore, R_eq = 10/3 = 3.33Ω.
Correct Answer: A — 3.33Ω
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Q. If a 10Ω resistor is connected in parallel with a 5Ω resistor, what is the total resistance? (2022)
A.
3.33Ω
B.
5Ω
C.
7.5Ω
D.
15Ω
Show solution
Solution
For resistors in parallel, 1/R_eq = 1/R1 + 1/R2 = 1/10 + 1/5 = 1/10 + 2/10 = 3/10. Therefore, R_eq = 10/3 = 3.33Ω.
Correct Answer: A — 3.33Ω
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Q. If a 15Ω resistor is connected in parallel with a 5Ω resistor, what is the equivalent resistance? (2023)
A.
3.75Ω
B.
4Ω
C.
5Ω
D.
10Ω
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Solution
1/R_eq = 1/15 + 1/5 = 1/15 + 3/15 = 4/15; R_eq = 15/4 = 3.75Ω.
Correct Answer: A — 3.75Ω
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Q. If a 2 kg object is dropped from a height, what is its velocity just before hitting the ground? (g = 9.8 m/s², h = 20 m) (2023)
A.
14 m/s
B.
19.6 m/s
C.
20 m/s
D.
28 m/s
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Solution
Using v² = u² + 2gh, where u = 0, we find v = √(2 * 9.8 * 20) = 19.6 m/s.
Correct Answer: B — 19.6 m/s
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Q. If a 2 kg object is dropped from a height, what is its velocity just before hitting the ground (g = 10 m/s²)? (2023)
A.
10 m/s
B.
20 m/s
C.
30 m/s
D.
40 m/s
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Solution
Using v = √(2gh), for h = 10 m, v = √(2 * 10 m/s² * 10 m) = √200 = 20 m/s.
Correct Answer: B — 20 m/s
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Q. If a 2 kg object is lifted to a height of 10 m, what is the potential energy gained by the object? (g = 9.8 m/s²)
A.
19.6 J
B.
98 J
C.
39.2 J
D.
78.4 J
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Solution
Potential Energy (PE) = mgh = 2 kg × 9.8 m/s² × 10 m = 196 J.
Correct Answer: B — 98 J
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Q. If a 2 kg object is moving with a velocity of 15 m/s, what is its kinetic energy?
A.
225 J
B.
150 J
C.
300 J
D.
450 J
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Solution
Kinetic Energy = 1/2 * m * v^2 = 1/2 * 2 kg * (15 m/s)^2 = 225 J.
Correct Answer: A — 225 J
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Q. If a 2 kg object is moving with a velocity of 3 m/s, what is its kinetic energy?
A.
9 J
B.
6 J
C.
3 J
D.
12 J
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Solution
Kinetic Energy = 0.5 * m * v² = 0.5 * 2 kg * (3 m/s)² = 9 J.
Correct Answer: A — 9 J
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Q. If a 4 kg object is moving with a speed of 5 m/s, what is its kinetic energy?
A.
50 J
B.
40 J
C.
100 J
D.
80 J
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Solution
Kinetic Energy (KE) = 0.5 × m × v² = 0.5 × 4 kg × (5 m/s)² = 0.5 × 4 × 25 = 50 J.
Correct Answer: D — 80 J
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Q. If a 5 kg object is dropped from a height of 10 m, what is its potential energy just before it hits the ground? (g = 9.8 m/s²)
A.
490 J
B.
980 J
C.
245 J
D.
2450 J
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Solution
Potential Energy (PE) = m × g × h = 5 kg × 9.8 m/s² × 10 m = 490 J.
Correct Answer: B — 980 J
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Q. If a 5 kg object is moving with a velocity of 3 m/s, what is its momentum? (2023)
A.
5 kg·m/s
B.
10 kg·m/s
C.
15 kg·m/s
D.
20 kg·m/s
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Solution
Momentum p = mv = 5 kg * 3 m/s = 15 kg·m/s.
Correct Answer: C — 15 kg·m/s
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Q. If a 5 kg object is subjected to a net force of 20 N, what is its acceleration? (2023)
A.
2 m/s²
B.
4 m/s²
C.
5 m/s²
D.
10 m/s²
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Solution
Using F = ma, we find a = F/m = 20 N / 5 kg = 4 m/s².
Correct Answer: B — 4 m/s²
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Q. If a 5Ω resistor is connected in series with a 10Ω resistor, what is the total resistance? (2022)
A.
15Ω
B.
5Ω
C.
10Ω
D.
20Ω
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Solution
In series, R_eq = R1 + R2 = 5Ω + 10Ω = 15Ω.
Correct Answer: A — 15Ω
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Q. If a 5Ω resistor is connected to a 10V source, what is the power dissipated? (2023)
A.
2W
B.
5W
C.
10W
D.
20W
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Solution
Power P = V²/R = (10V)² / 5Ω = 100 / 5 = 20W.
Correct Answer: C — 10W
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Q. If a 6Ω resistor is connected in parallel with a 3Ω resistor, what is the equivalent resistance? (2023)
A.
2Ω
B.
1.5Ω
C.
4Ω
D.
9Ω
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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: A — 2Ω
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