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. Which of the following statements is incorrect about a Plane Mirror?
[A] The focal length of a plane mirror is infinity
[B] Its optical power is one
[C] It forms a virtual image of a real object
[D] It is used in constructing periscope
Show Answer
Correct Answer: B [Its optical power is one]
Notes:
Second statement is incorrect because the optical power of plane mirror is zero.
2. Hydraulic Brakes work on which principle?
[A] Pascal’s Principle
[B] Archimedes Principle
[C] Newton’s Laws
[D] Casini’s Laws
Show Answer
Correct Answer: A [Pascal’s Principle]
Notes:
In 1647 the French scientist Blaise Pascal (1623–1662) discovered that water exerts the same pressure in all directions. This statement is known as Pascal’s Principle.
Pascal’s law states that increase in pressure at a point in the enclosed liquid in equilibrium is transmitted equally in all directions in liquid and to the Walls of the container. The working of hydraulic lift, hydraulic press and hydraulic brakes are based on Pascal’s law.
3. Which among the following defines gravitational mass?
[A] Ratio of weight of a body and acceleration due to gravity
[B] Ratio of Acceleration due to gravity and weight of a body
[C] matter contained in a body
[D] None of the above
Show Answer
Correct Answer: A [Ratio of weight of a body and acceleration due to gravity]
Notes:
Gravitational mass is the Ratio of weight of a body and acceleration due to gravity. Gravitational mass is the mass of a body as measured by its gravitational attraction for other bodies.
4. Which among the following is measured by an Odometer?
[A] Pressure
[B] Height
[C] Distance
[D] Velocity
Show Answer
Correct Answer: C [Distance]
Notes:
An odometer is an instrument used for measuring the distance. It measures distance traveled by a vehicle such as a bicycle or car. The device may be electronic, mechanical, or a combination of the two.
5. In recent times, the “dynamic brake system” is becoming popular in modern railways. The dynamic brake system coverts Kinetic energy to__:
[A] Potential energy
[B] Electricity
[C] Sound energy
[D] Magnetic energy
Show Answer
Correct Answer: B [ Electricity]
Notes:
Modern engines also have, additionally, dynamic brake system which works on the principle of converting kinetic energy of the moving train to electricity making the electric motors to work as generators.
6. An Electric generator is based on which of the following scientific principles?
[A] Faraday’s law of Electromagnetic Induction
[B] Super Conductivity
[C] Laws of Thermodynamics
[D] Newton’s Law of Motion
Show Answer
Correct Answer: A [Faraday’s law of Electromagnetic Induction]
Notes:
An Electric generator works on the principle of Faraday’s law of Electromagnetic Induction. An electric generator uses mechanical energy to generate electricity applying Faraday’s law of induction. It spins a coil at a constant rate in a magnetic field to induce an oscillating emf.
7. What is the force of attraction between any two bodies by virtue of their masses is called?
[A] Electromagnetic Force
[B] Gravitational Force
[C] Centripetal Force
[D] Nuclear Force
Show Answer
Correct Answer: B [Gravitational Force]
Notes:
Gravitational Force is the force of attraction between any two bodies by virtue of their masses. It is a universal force and every object in the universe experiences gravitational force due to every other object.
8. Which of the following is NOT a unit for measuring pressure?
[A] bar
[B] torr
[C] Pascal
[D] shake
Show Answer
Correct Answer: D [ shake ]
Notes:
bar, torr and Pascal are the units used for measuring pressure whereas shake is a unit of time. 1 bar = 105 Pa 1 bar = 760 torr 1 bar = 1 atmospheric pressure Shake is the smallest practical unit of time. 1 shake = 10-8s
9. What is the value of Triple point of water?
[A] 273.16 K
[B] 273.16° C
[C] 0° C
[D] -273.16 K
Show Answer
Correct Answer: A [ 273.16 K ]
Notes:
Triple point of water is the temperature at which ice, water and water vapours coexist. The value of Triple point of water is 273.16 K Kelvin is the S.I unit of Temperature represented by symbol K.
10. Which of these pairs has the same unit of measurement?
[A] Rate of flow and Acceleration
[B] Impulse and Moment of Force
[C] Rydberg constant and Gas constant
[D] Pressure and Coefficient of Elasticity
Show Answer
Correct Answer: D [ Pressure and Coefficient of Elasticity ]
Notes:
Pressure and Coefficient of Elasticity have the same unit i.e. N m-2 (Newton per metre square) Other important units: Rate of Flow: m3s-1 Acceleration: ms-2 Rydberg constant: 1/m Gas constant: J/K Impulse: Ns Moment of Force: Nm
