Physics (Part-IV) (Railway)

1. The amount of water vapour present in the air is called- [RRB RPF Constable Exam, 15.02.2019 Shift-I]

(1) Heat
(2) Density
(3) Absolute Humidity
(4) Viscosity

Correct Answer: (3) Absolute Humidity

Solution:The amount of water vapor in the air is called absolute humidity.

• The amount of water vapor in the air as compared with the amount of water that the air could hold is called relative humidity.

2. What is the refractive index of water? [RRB RPF Constable Exam, 18.02.2019 Shift-II]

(1) 1.71
(2) 1.33
(3) 1.003
(4) 1.52

Correct Answer: (2) 1.33

Solution:The refractive index is the measure of bending of a light ray when passing from one medium to another.

• The refractive index is 1.333.

3. What will be the magnetic field with in a solenoid? [RRB RPF Constable Exam, 18.02.2019 Shift-II]

(1) Uneven
(2) Random
(3) Similar
(4) Discrete

Correct Answer: (3) Similar

Solution:Inside a solenoid the magnetic field lines will be straight lines and the field will be strong.

• Outside the solenoid the magnetic field will be weak and the field lines will curl up to form closed loops. Hence, the magnetic field inside a solenoid will be same.

4. Which of the following represents mirror formula? [RRB RPF Constable Exam, 18.02.2019 Shift-II]

(1) 1/v-1/u = 1/f
(2) f=v+u+w
(3) 1/v+1/u = 1/f
(4) vu=f

Correct Answer: (3) 1/v+1/u = 1/f

Solution:The mirror formula is represented by the following equation :

l/f = 1/v+1/u

5. The amount of heat required to convert ice into water is called- [RRB RPF Constable Exam, 19.02.2019 Shift-II]

(1) Latent heat of condensation of ice
(2) Latent Heat of vapouration
(3) Latent heat of sublimation
(4) The Latent heat of fusion of ice

Correct Answer: (4) The Latent heat of fusion of ice

Solution:The amount of heat required to convert per unit mass of the ice into the water at 0°C temperature is called the latent heat of fusion of ice.

6. In the human eye, image is on the_________. [RRB RPF Constable Exam, 19.02.2019 Shift-II]

(1) Pupil
(2) the Pupil of the eye
(3) Retina
(4) Ciliary Muscles

Correct Answer: (3) Retina

Solution:The eye lens is flexible and thus can change its focal length and shape with the help of ciliary muscles.

• Behind the eye lens is the retina on which the image is formed in the eye

7. The color band obtained due to diffusion of light is called- [RRB RPF Constable Exam, 19.02.2019 Shift-II]

(1) Coherent scattering
(2) Constructive interference
(3) Spectrum
(4) Base

Correct Answer: (3) Spectrum

Solution:Dispersion is the phenomenon of splitting of polychromatic light into its constituent colours.

• The band of colours obtained on the screen on passing white light through a prism is called a spectrum.

8. The light ray passing through the eyes of a lens, is___________. [RRB RPF Constable Exam, 19.02.2019 Shift-II]

(1) Invisible
(2) Emerge without deviation
(3) Turns towards the centre
(4) Turns to spread center

Correct Answer: (2) Emerge without deviation

Solution:The light rays refract twice: first when entering the lens and second when leaving the lens. Only the light rays passing through the center of the lens remain straight. Parallel light rays that pass through a concave lens do not meet.

9. Which of the following devices is used to measure relatively high temperatures, such as are "encountered in furnaces? [RRB NTPC CBT-1 Exam, 07.01.2021 (Shift-II)]

(1) Ammeter
(2) Fluxmeter
(3) Pyrometer
(4) Bolometer

Correct Answer: (3) Pyrometer

Solution:Pyrometer is a device for measuring relatively high temperatures, such as are encountered in furnaces.

• Ammeter is an instrument for measuring either direct or alternating electric current, In amperes.

• Fluxmeter is the device used to measure the magnetic flux of a permanent magnet.

• An instrument that is used to detect as well as measure the microwave energy radiation and heat is known as a bolometer.

10. Which of the two colours of spectrum forms the extremes? [RRB NTPC CBT-1 Exam, 07.01.2021 (Shift-II)]

(1) Violet and Red
(2) Yellow and Orange
(3) Blue and Green
(4) Red and Orange

Correct Answer: (1) Violet and Red

Solution:Violet bends the most because it has shorter wavelength compared to other colours and red colour bends the, least and can be seen at the extreme end opposite to each other in colour spectrum.