Physics (Part-III) (Railway)

Total Questions: 50

41. Which device is used to convert physical signal into an electrical signal? [RRB RPF Constable Exam, 25.01.2019 Shift-I]

Correct Answer: (4) Transducer
Solution:Transducers are used in electronic communications systems to convert signals of various physical forms to electronic signals, and vice versa.

• They produce an electrical signal proportional to the input (physical quantity).

42. Which of the following is called a Voltaic Cell? [RRB RPF Constable Exam, 25.01.2019 Shift-I]

Correct Answer: (4) Galvanic Cell
Solution:An electrochemical cell that converts the chemical energy of spontaneous redox reactions into electrical energy is known as a galvanic cell or a voltaic cell.

• A galvanic cell or voltaic cell is named after the scientists Luigi Galvani and Alessandro Volta, respectively.

43. The product of mass and velocity of an object is called_______. [RRB RPF Constable Exam, 25.01.2019 Shift-III)]

Correct Answer: (3) Momentum
Solution:The product of mass and velocity is called momentum.

• It is defined as a quantity of motion of a body.

44. The sound of a single frequency is called__________. [RRB RPF Constable Exam, 25.01.2019 Shift-III]

Correct Answer: (2) Tone
Solution:Tone is the sound of a single frequency.

• A sound produced after the mixing of several frequencies is known as a node.

45. The product of mass and velocity is_________. [RRB RPF Constable Exam, 02.02.2019 Shift-I]

Correct Answer: (1) Impulse
Solution:The product of mass and velocity of an object is called momentum. (Symbol P) given by the equation P = mv.

• Momentum is a vector quantity that has the same direction as the velocity of the object.

46. Which property of a conductor prevents flow of electrons? [RRB RPF Constable Exam, 02.02.2019 Shift-I]

Correct Answer: (3) Resistance
Solution:Resistance is a measure of the amount of resistance that a conductor can provide to the free flow of its electrons.

• The length, area, and nature of the material, act as important factors in determining the resistance of the conductor.

47. Which of the following works on the basis of electromagnetic induction? [RRB RPF Constable Exam, 02.02.2019 Shift-I]

Correct Answer: (1) Generator
Solution:Electric generators work on the principle of electromagnetic induction.

• Electricity is generated by гоtating a coil inside a magnetie field.

48. Which optical device is made from calcite crystals and is used for observation and production of plain polarized light? [RRB RPF Constable Exam, 11.02.2019 Shift-I]

Correct Answer: (2) Nichol Prism
Solution:Nicolas prism is an optical device which is used for producing and analyzing plain polarized light in practice.

• It is made in such a way that it eliminates one of the rays by total internal reflection, i.e the ordinary ray is eliminated and only the extraordinary ray is transmitted through the prism.

49. Due to the process of electrification between the earth and the clouds or different surfaces of the clouds: [RRB RPF Constable Exam, 15.02.2019 Shift-I]

Correct Answer: (1) Lightning
Solution:The process of electric discharge between clouds and the earth or between different clouds causes lightning.

• The process of electric discharge can occur between two or more clouds or between clouds and the earth.

50. On keeping a coin inside water, it appears to be standing due to? [RRB RPF Constable Exam, 15.02.2019 Shift-I]

Correct Answer: (1) Refraction of light
Solution:This is reason of refraction of light.

• As light passes from water to air, it bends away from the normal. The refracted rays appear to come from a point above the actual position of the coin, hence the coin appears raised.