Physics · Science General
Optics and Light Properties
2,019 Questions
Optics and light properties focus on the behavior of light, including reflection, refraction, dispersion, and polarization. This topic also covers the wave nature of light, illumination, and the functioning of optical instruments like microscopes. Questions on these concepts are common in general science sections of SSC, Railways, and State exams.
Reflection and mirrorsRefraction and mediumsLight wave theoriesPolarization and intensity
Optics and Light Properties Questions
-
Opaque
-
Tannery
-
Tanslucent
-
Reduce
C
Correct answer
Explanation
A translucent object allows light to pass through but diffuses it so you cannot see clearly through it (unlike transparent). Opaque blocks light completely.
-
intensity of illumination
-
distance
-
time
-
parallax
B
Correct answer
Explanation
Light year is a unit of distance.
-
Radio rays
-
Ultraviolet rays
-
X-rays
-
Infrared rays
D
Correct answer
Explanation
Infrared rays have longer wavelengths than visible light and can penetrate haze, fog, and smoke more effectively because they scatter less than visible light. This makes infrared radiation useful for thermal imaging, night vision, and surveillance applications. Radio waves also penetrate but lack the resolution for clear viewing. UV and X-rays are more strongly scattered.
-
frequency
-
wavelenght
-
amplitude
-
none of these
D
Correct answer
Explanation
The speed of light in vacuum is a fundamental constant c = 3 x 10^8 m/s. It does NOT depend on frequency, wavelength, or amplitude. The relationship c = f × λ means that if you change frequency, wavelength changes automatically to keep c constant. Only in a medium does the speed change, and that depends on the medium's properties, not the wave characteristics.
-
As a parallel beam in one direction
-
As diffused beam in all directions
-
As parallel beam in all directions
-
As a diffused beam in one direction
A
Correct answer
Explanation
An optically plane surface reflects a beam of light as a parallel beam in one direction (regular reflection). This is because all rays strike at the same angle of incidence and reflect at the same angle of reflection, maintaining parallelism. A diffused beam occurs with rough surfaces where light scatters in different directions.
-
a red light
-
a green light
-
a white light
-
none of these
B
Correct answer
Explanation
When an aircraft crosses from your left (port side) to right (starboard side) at a right angle, you are viewing its starboard side. Aircraft navigation lights are red on the port (left) wing and green on the starboard (right) wing, with white at the tail. Therefore, you see the green light on the starboard wing as it crosses from left to right. You would not see red (port side) or white (tail-only visible from behind) in this crossing scenario.
-
In sunglasses
-
In filters for cameras
-
In mirrors
-
None of these
C
Correct answer
Explanation
Polarized glass is used in sunglasses to reduce glare from reflective surfaces, in camera filters to manage reflections and enhance contrast, but standard mirrors do not use polarized glass. Mirrors work by specular reflection using metallic coatings (silver, aluminum) on glass, which doesn't require polarization. While polarizing mirrors exist for specialized applications, standard mirrors are not polarized.
-
3.5 NM
-
2.5 NM
-
1.0 NM
-
0.5 NM
C
Correct answer
Explanation
Special VFR (SVFR) clearance requires minimum visibility of 1.0 NM. This reduced standard (compared to regular VFR) allows operations in controlled airspace when weather is below standard VFR minima but still permits safe visual flight.
-
Total Darkness
-
Partial darkness
-
Fluorescent
-
Incandescence light
A
Correct answer
Explanation
Umbra refers to the darkest part of a shadow during an eclipse, where the light source is completely blocked. It represents total darkness. Penumbra is the term for partial darkness where only part of the light source is blocked. The other options (fluorescent, incandescent) refer to light-producing mechanisms, not shadow concepts.
-
Agar
-
Tin foil
-
Mica
-
Excised tips
C
Correct answer
Explanation
Mica pieces were used by Boysen Jensen in his experiment.
-
refraction
-
light scattering
-
reflection
-
interference
A
Correct answer
Explanation
Refraction causes the swimming pool to appear shallower than it actually is. Light rays from the bottom bend (refract) away from the normal as they pass from water to air, making the virtual image appear raised. This is why objects underwater seem closer to the surface.
-
reflection of light
-
diffraction of light
-
refraction of light
-
polarisation of light
C
Correct answer
Explanation
Due to refraction of light
-
is absorbed least by air
-
is soothing to eye
-
is scattered least
-
has least chemical effect
C
Correct answer
Explanation
Red light has the longest wavelength in the visible spectrum, making it least susceptible to Rayleigh scattering by atmospheric particles like dust and water droplets. This property allows red light to travel longer distances with minimal dispersion, making it ideal for danger signals that need maximum visibility. Blue light scatters most, which is why the sky appears blue.
-
Wave Division Multiplexing (WDM) is called the optical equivalent of Frequency Division Multiplexing (FDM) .
-
FDM modulates the several data streams on to a different part of light spectrum.
-
TDM repeatedly transmits a fixed sequence of time slots over a single transmission channel.
-
Television transmitter is an example of FDM.
-
None of the above
B
Correct answer
Explanation
This is false statement as WDM modulates the several data streams on to a different part of light spectrum by using optical fiber in multiplexing.
-
holography
-
holographic screen
-
computer generated holography
-
volumetric display device
B
Correct answer
Explanation
A holographic screen is a display technology that uses coated glass media for the projection surface of a video projector. Holographic refers to the coating that bundles light using formed microlenses. The lens design and attributes match the holographic area.