Physics MCQs
Physics Objective (Multiple Choice) General Knowledge & General Science Questions & Answers for SSC-CGL, UPPSC, NDA, CDS and all one day examinations of India.
1. If in a closed room , the door of a refrigerator is kept open for some time , the temperature of room will ?
[A] Increase
[B] Decrease
[C] Remains same
[D] First decrease then become stable
Show Answer
Correct Answer: A [Increase]
Notes:
A refrigerator is like a heat engine. It extracts heat from low temperature reservoir and transfer it to high temperature. If a refrigerator’s door is kept open, then room will become hot, because then refrigerator exhaust more heat into the room than earlier.
2. Which among the following defines cohesive force?
[A] the force of attraction acting between the molecules of same material
[B] the force of attraction acting between the molecules of different material
[C] the force of attraction acting between the atoms of same material
[D] None of the above
Show Answer
Correct Answer: A [the force of attraction acting between the molecules of same material]
Notes:
The force of attraction acting between the molecules of same material is known as cohesive force. Cohesive force is the action or property of like molecules sticking together, being mutually attractive.
3. Which among the following is true about latent heat ?
[A] It causes change in temperature as well as change in state or phase
[B] It causes change in temperature only
[C] It causes change in state or phase but not in temperature
[D] It causes change in Pressure
Show Answer
Correct Answer: C [It causes change in state or phase but not in temperature]
Notes:
The latent heat Latent heat is energy released or absorbed, by a body or a thermodynamic system, during a constant-temperature process. It causes change in state or phase but not in temperature.
4. Steam at 100 degree centigrade causes more severe burns. Which of the following phenomena will you use to explain this?
[A] Specific heat
[B] Latent heat
[C] Fusion
[D] Fission
Show Answer
Correct Answer: B [Latent heat]
Notes:
Latent heat is energy released or absorbed, by a body or a thermodynamic system, during a constant-temperature process. So steam at 100 degree centigrade causes more severe burns.
5. Which of the following is not a valid conservation law of classical Physics?
[A] Law of conservation of energy
[B] Law of conservation of current
[C] Law of conservation of angular momentum
[D] Law of conservation of charge
Show Answer
Correct Answer: B [Law of conservation of current]
Notes:
The following laws are dealt with in the classical physics: 1. Law of conservation of energy 2. Law of conservation of angular momentum 3. Law of conservation of linear momentum 4. Law of conservation of charge
6. 1 femto metre is equal to how many metres?
[A] 10-12
[B] 10-14
[C] 10-15
[D] 1-24
Show Answer
Correct Answer: C [ 10-15 ]
Notes:1 femto metre is equal to 10
-15 metre. Some other metric prefixes are:
- nano = 10-9
- pico = 10-12
- atto = 10-18
- tera = 1012
- peta = 10-15
- exa = 10-18
7. Which of the following is the unit of Solid Angle?
[A] radian
[B] steradian
[C] m2
[D] π
Show Answer
Correct Answer: B [ steradian ]
Notes:
Steradian is the unit of Solid Angle (Angle in Space). One steradian is defined as the solid angle of a sphere subtended at the centre of a sphere by that surface of the surface whose area is equal to the square of the sphere’s radius. Its symbol is sr.
8. Which of the following is true about displacement of an object?
[A] It is always equal to the distance travelled by the object
[B] It can be less than the distance travelled by the object
[C] It can be greater than the distance travelled by the object
[D] It always less than the distance travelled by the object
Show Answer
Correct Answer: B [It can be less than the distance travelled by the object]
Notes:
The displacement is the shortest distance between the initial and final position of an object in the given time. The displacement of an object is a vector quantity. It can be less than or equal to the distance but can never be greater than the distance travelled by that object
9. Which of the following options is a representation of non-uniform motion?
[A] Equal displacements in unequal intervals of time
[B] Unequal displacements in unequal intervals of time
[C] Equal displacements in equal intervals of time
[D] Unequal displacements in equal intervals of time
Show Answer
Correct Answer: A [Equal displacements in unequal intervals of time]
Notes:
Non-uniform motion refers to the motion where the objects cover equal distances in unequal time or unequal distances in equal time. In other words, when the speed of the object is not constant, or the direction of movement of an object changes, then it is in non-uniform motion. An example of this can be any vehicle moving on a crowded city road, where it constantly changes its speed.
10. Which of the following is/are correct about Kinetic energy?
[A] Kinetic energy can be positive or negative
[B] Kinetic energy is independent of frame of reference
[C] Both a and b
[D] None of the above
Show Answer
Correct Answer: D [None of the above]
Notes:
Kinetic energy of a body is half the product of mass of the body and square of the velocity of the body. K.E = 1/2(mv2) Kinetic energy depends on the frame of reference. Kinetic energy of a body is always positive.
