General Science Physics Questions
21. Which of the following is correct as per the second law of thermodynamics?
[A] Efficiency of a heat engine can never be zero
[B] Efficiency of a heat engine can never be unity
[C] Efficiency of a heat engine is always unity
[D] None of the above
[B] Efficiency of a heat engine can never be unity
Notes:
The Second Law of Thermodynamics gives a fundamental limitation to the efficiency of a heat engine and the co-efficient of performance of a refrigerator. In simple terms, it says that efficiency of a heat engine can never be unity.
22. Which of the following is a law of reflection?
[A] Angle of incidence is equal to the angle of reflection
[B] Angle of incidence is equal to twice the angle of reflection
[C] Angle of incidence is equal to half of the angle of reflection
[D] Angle of incidence is always complimentary to the angle of reflection
[A] Angle of incidence is equal to the angle of reflection
Notes:
As per one of the laws of reflection, the angle of incidence is always equal to the angle of reflection.
23. What is the role of salt bridge?
- [A] allows the ions to flow from one half cell to another
- [B] prevents the flow of solutions from one half cell to another
- [C] Both a and b
- [D] None of the above
[C] Both a and b
Notes:
The salt bridge allows the ions to flow from one half cell to another, but prevents the flow of solutions.
24. Which of the following is correct about an electric motor?
[A] It converts potential energy to chemical energy
[B] It converts electrical energy to mechanical energy
[C] It converts mechanical energy to electrical energy
[D] None of the above
[B] It converts electrical energy to mechanical energy
Notes:
An electric motor is a rotating device that converts electrical energy to mechanical energy.
25. Which of the following is the function of calorimeter?
[A] Measures the amount of calories in the body
[B] Measures the heat of chemical reactions and physical change
[C] Measures the density of an object
[D] None of the above
[B] Measures the heat of chemical reactions and physical change
Notes:
A calorimeter is an object used for calorimetry, or the process of measuring the heat of chemical reactions or physical changes as well as heat capacity. Differential scanning calorimeters, isothermal micro calorimeters, titration calorimeters and accelerated rate calorimeters are among the most common types.
26. Which of the following substances conducts current in the solid state?
[A] Iodine
[B] Diamond
[C] Graphite
[D] Sodium chloride
[C] Graphite
Notes:
Graphite is a form of carbon and is a conductor of electricity. The carbon atoms’ electrons can move within the material. Graphite is only a fairly good conductor and longer circuits have more resistance to current flow.
27. Which of the following energy transformation takes place in microphone?
[A] Sound into electrical energy
[B] Electrical into sound energy
[C] Sound into mechanical energy
[D] Mechanical into sound energy
[B] Electrical into sound energy
Notes:
Microphone is a transducer that converts sound into an electrical energy. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public events, motion picture production, live and recorded audio engineering, sound recording, radio and television broadcasting.
28. Why does man weigh more at the poles than at the equator?
[A] Because there is no atmosphere at the poles
[B] Because gravitational pull is more at the poles
[C] Because gravitational pull is less at the poles
[D] None of the above
[B] Because gravitational pull is more at the poles
Notes:
If we see the shape of the Earth, it is flatter at the poles and bulged at the equator. Therefore, the distance of the poles from the centre of the Earth is less than distance of the equator from the centre of the Earth. Now, recall the formula of gravitational force between two objects —F = (G * M1 * M2)/R^2. Here, R is the distance between the two objects. Distance is inversely proportional to the Force. Since the distance at the equator is more, it will have less gravitational force. Lesser the gravitational force, lesser will be the weight of the object. Since the distance between the poles is less, there will be more gravitational force. More is the gravitational force, more will be the weight of the object. Hence, the object will weigh minimum at the equator and maximum at the poles.
29. Which of the following terms is used to denote the heavy rocks of the lithosphere?
[A] Substratum
[B] SIAL
[C] SIMA
[D] None of the above
[C] SIMA
Notes:
In geology, sima is the name for the lower layer of the Earth’s crust which consists of heavy rocks of the lithosphere. The name ‘sima’ was taken from the first two letters of silica and of magnesia. Comparable is the name ‘sial’ which is the name for the upper layer of the Earth’s continental crust.
30. Which of the following pairs of physical quantities have the same dimensions?
[A] Force and Power
[B] Work and Power
[C] Work and Energy
[D] Momentum and Power
[C] Work and Energy
Notes:
The term energy is used to describe the capacity of a system to do work on another system. Energy of all types (Surface tension, Kinetic, Potential etc.) have the same dimension and unit as that of work with same dimensional formula of M1L2T-2. In the SI system, both have the same units of Newton meter.
