Q. A force of 50 N is applied to a 25 kg object. What is the acceleration of the object? (2019)
A.
1 m/s²
B.
2 m/s²
C.
3 m/s²
D.
4 m/s²
Show solution
Solution
Using F = ma, a = F/m = 50 N / 25 kg = 2 m/s².
Correct Answer:
B
— 2 m/s²
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Q. A force of 50 N is applied to a 25 kg object. What is the object's acceleration? (2020)
A.
1 m/s²
B.
2 m/s²
C.
3 m/s²
D.
4 m/s²
Show solution
Solution
Using F = ma, a = F/m = 50 N / 25 kg = 2 m/s².
Correct Answer:
B
— 2 m/s²
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Q. A force of 50 N is applied to move an object 4 m. How much work is done?
A.
100 J
B.
150 J
C.
200 J
D.
250 J
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Solution
Work = Force * Distance = 50 N * 4 m = 200 J.
Correct Answer:
C
— 200 J
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Q. A gas expands from 2 L to 5 L at a constant pressure of 1 atm. How much work is done by the gas? (2023)
A.
3 L·atm
B.
5 L·atm
C.
2 L·atm
D.
1 L·atm
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Solution
Work done by the gas during expansion at constant pressure is W = PΔV. Here, ΔV = 5 L - 2 L = 3 L, so W = 1 atm * 3 L = 3 L·atm.
Correct Answer:
A
— 3 L·atm
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Q. A gas expands from a volume of 2 m³ to 5 m³ at a constant pressure of 100 kPa. What is the work done by the gas? (2022)
A.
300 kJ
B.
500 kJ
C.
700 kJ
D.
3000 kJ
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Solution
Work done (W) = P * ΔV = 100 kPa * (5 m³ - 2 m³) = 100 kPa * 3 m³ = 300 kJ.
Correct Answer:
A
— 300 kJ
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Q. A gas expands from volume V1 to V2 at constant pressure P. What is the work done by the gas? (2022)
A.
P(V2 - V1)
B.
P(V1 + V2)
C.
P(V1 * V2)
D.
P(V1 - V2)
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Solution
Work done (W) = P * ΔV = P * (V2 - V1).
Correct Answer:
A
— P(V2 - V1)
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Q. A gas expands from volume V1 to V2 at constant temperature. If the initial pressure is P1, what is the final pressure P2? (2020)
A.
P1(V1/V2)
B.
P1(V2/V1)
C.
P1
D.
P1/2
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Solution
According to Boyle's Law, P1V1 = P2V2, thus P2 = P1(V1/V2).
Correct Answer:
A
— P1(V1/V2)
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Q. A gas expands isothermally at 300 K and absorbs 600 J of heat. What is the work done by the gas? (2023)
A.
600 J
B.
300 J
C.
900 J
D.
0 J
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Solution
In an isothermal process, the work done by the gas is equal to the heat absorbed. Therefore, work done = 600 J.
Correct Answer:
A
— 600 J
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Q. A gas expands isothermally at 300 K from a volume of 1 m³ to 2 m³. If the pressure of the gas is 100 kPa, what is the work done by the gas? (2020)
A.
0 kJ
B.
10 kJ
C.
20 kJ
D.
30 kJ
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Solution
Work done (W) = P * ΔV = 100 kPa * (2 m³ - 1 m³) = 100 kPa * 1 m³ = 100 kJ = 10 kJ.
Correct Answer:
B
— 10 kJ
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Q. A gas expands isothermally at 300 K from a volume of 1 m³ to 2 m³. If the pressure at the initial state is 100 kPa, what is the work done by the gas?
A.
0 kJ
B.
100 kJ
C.
150 kJ
D.
200 kJ
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Solution
Work done (W) = nRT ln(Vf/Vi). Here, nRT = PVi = 100 kPa * 1 m³ = 100 kJ. W = 100 kJ * ln(2) ≈ 69.3 kJ.
Correct Answer:
B
— 100 kJ
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Q. A gas is compressed adiabatically. Which of the following statements is true? (2023)
A.
Temperature increases
B.
Pressure decreases
C.
Volume increases
D.
Internal energy decreases
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Solution
In an adiabatic compression, the temperature of the gas increases due to work done on it.
Correct Answer:
A
— Temperature increases
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Q. A gas is compressed isothermally from a volume of 4 L to 1 L at a constant temperature of 300 K. If the initial pressure is 1 atm, what is the final pressure?
A.
4 atm
B.
3 atm
C.
2 atm
D.
1 atm
Show solution
Solution
Using Boyle's Law, P1V1 = P2V2, we find P2 = P1 * (V1/V2) = 1 atm * (4 L / 1 L) = 4 atm.
Correct Answer:
A
— 4 atm
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Q. A jar contains 10 candies, 4 of which are chocolate. What is the probability of selecting a chocolate candy?
A.
2/5
B.
1/2
C.
4/10
D.
3/10
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Solution
Probability of chocolate candy = 4/10 = 2/5.
Correct Answer:
B
— 1/2
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Q. A jar contains 4 green, 5 yellow, and 1 red marble. What is the probability of picking a yellow marble? (2019)
A.
1/10
B.
1/5
C.
1/2
D.
5/10
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Solution
Total marbles = 4 + 5 + 1 = 10. Probability of yellow = 5/10 = 1/2.
Correct Answer:
D
— 5/10
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Q. A jar contains 6 green and 4 yellow marbles. What is the probability of picking a yellow marble?
A.
2/5
B.
1/2
C.
4/10
D.
3/5
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Solution
Total marbles = 6 + 4 = 10. Probability of yellow marble = 4/10 = 2/5.
Correct Answer:
A
— 2/5
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Q. A jar contains 7 red, 5 blue, and 8 green marbles. What is the probability of selecting a blue marble?
A.
5/20
B.
1/4
C.
1/5
D.
1/3
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Solution
Total marbles = 7 + 5 + 8 = 20. Probability of blue marble = 5/20 = 1/4.
Correct Answer:
A
— 5/20
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Q. A jar contains 8 red and 4 blue marbles. What is the probability of selecting a blue marble?
A.
1/3
B.
1/2
C.
1/4
D.
1/5
Show solution
Solution
Total marbles = 8 + 4 = 12. Probability of blue marble = 4/12 = 1/3.
Correct Answer:
A
— 1/3
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Q. A jar contains 8 red, 6 blue, and 4 green marbles. What is the probability of selecting a blue marble?
A.
1/3
B.
1/4
C.
2/5
D.
3/10
Show solution
Solution
Total marbles = 8 + 6 + 4 = 18. Probability of blue marble = 6/18 = 1/3.
Correct Answer:
D
— 3/10
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Q. A lens has a focal length of -15 cm. What type of lens is it? (2020)
A.
Convex lens
B.
Concave lens
C.
Bifocal lens
D.
Cylindrical lens
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Solution
A negative focal length indicates that the lens is a concave lens.
Correct Answer:
B
— Concave lens
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Q. A lens has a focal length of 15 cm. What is the power of the lens? (2023)
A.
+6.67 D
B.
+7.5 D
C.
+10 D
D.
+15 D
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Solution
Power (P) of a lens is given by P = 1/f (in meters). Here, f = 15 cm = 0.15 m, so P = 1/0.15 = +6.67 D.
Correct Answer:
B
— +7.5 D
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Q. A light ray strikes a plane mirror at an angle of 30 degrees to the normal. What is the angle of reflection? (2023)
A.
30 degrees
B.
60 degrees
C.
90 degrees
D.
45 degrees
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Solution
According to the law of reflection, the angle of reflection is equal to the angle of incidence. Therefore, the angle of reflection is also 30 degrees.
Correct Answer:
A
— 30 degrees
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Q. A light ray strikes a plane mirror at an angle of incidence of 30 degrees. What is the angle of reflection? (2021)
A.
30 degrees
B.
60 degrees
C.
90 degrees
D.
45 degrees
Show solution
Solution
According to the law of reflection, the angle of reflection is equal to the angle of incidence. Therefore, the angle of reflection is also 30 degrees.
Correct Answer:
A
— 30 degrees
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Q. A long straight wire carries a current I. What is the direction of the magnetic field at a point located directly above the wire? (2020)
A.
Towards the wire
B.
Away from the wire
C.
Clockwise
D.
Counterclockwise
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Solution
Using the right-hand rule, the magnetic field direction at a point above the wire is away from the wire.
Correct Answer:
B
— Away from the wire
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Q. A loop of wire is moved into a magnetic field at a constant speed. What happens to the induced current as the loop enters the magnetic field? (2023)
A.
It increases
B.
It decreases
C.
It remains constant
D.
It becomes zero
Show solution
Solution
As the loop enters the magnetic field, the change in magnetic flux increases, leading to an increase in the induced current.
Correct Answer:
A
— It increases
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Q. A loop of wire is placed in a changing magnetic field. What phenomenon occurs? (2021)
A.
Electromagnetic induction
B.
Magnetic resonance
C.
Electrolysis
D.
Magnetic levitation
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Solution
When a loop of wire is placed in a changing magnetic field, electromagnetic induction occurs, generating an electromotive force (EMF) in the loop.
Correct Answer:
A
— Electromagnetic induction
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Q. A loop of wire is placed in a uniform magnetic field. If the field strength is increased, what happens to the induced current? (2023)
A.
It increases
B.
It decreases
C.
It remains the same
D.
It becomes zero
Show solution
Solution
If the magnetic field strength increases, the magnetic flux through the loop increases, inducing a current according to Faraday's law.
Correct Answer:
A
— It increases
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Q. A loop of wire is placed in a uniform magnetic field. If the magnetic field is increased uniformly, what happens to the induced current in the loop?
A.
It increases
B.
It decreases
C.
It remains constant
D.
It becomes zero
Show solution
Solution
According to Faraday's law, an increase in magnetic field through the loop induces a current in the loop, which increases as the rate of change of magnetic flux increases.
Correct Answer:
A
— It increases
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Q. A loop of wire is rotated in a uniform magnetic field. What is the effect on the induced current? (2019)
A.
It remains constant
B.
It reverses direction
C.
It increases
D.
It decreases
Show solution
Solution
As the loop rotates, the angle between the magnetic field and the normal to the loop changes, which causes the direction of the induced current to reverse periodically.
Correct Answer:
B
— It reverses direction
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Q. A machine does 1200 J of work in 60 seconds. What is its efficiency if the input energy is 2000 J? (2022)
A.
60%
B.
70%
C.
80%
D.
90%
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Solution
Efficiency = (Output Work / Input Energy) * 100 = (1200 J / 2000 J) * 100 = 60%.
Correct Answer:
A
— 60%
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Q. A machine does 1500 J of work in 30 seconds. What is its power output?
A.
50 W
B.
30 W
C.
75 W
D.
100 W
Show solution
Solution
Power (P) = Work (W) / Time (t). P = 1500 J / 30 s = 50 W.
Correct Answer:
A
— 50 W
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