1st Year Physics Chapter 10 Optical Instruments Mcqs With Answers

1st Year Physics Chapter 10 Optical Instruments Mcqs With Answers is about optical instruments based on principles of Reflection and Refraction. Every optical instrument has its own magnifying and resolving power. For the purpose of viewing small objects, a microscope is used. Different microscopes are used for different purposes. An Astronomical Telescope is used to see distant objects. In order to study spectra of different light sources, Spectrometer is used.  Fibre optic is a very thin wire used to send information within a form of light. It is also used to send sound waves. But the information can be lost in fibre optics due to some defects.

1st Year Physics Chapter 10 Key Points

 

1st Year Physics Chapter 10 Optical Instruments Mcqs

 

Question#1. Large astronomical telescopes are of which type?

• Refraction
• Reflection
• Diffraction
• Dispersing

Question#2. A point where the incident parallel rays of light converge or appear to diverge after passing through a lens is called?

• Center of curvature
• Focus
• Optical center
• Aperture

Question#3. Who invented photophone?

• Graham Bell
• Galileo
• Torricelli
• Maxwell

Question#4. In going from a denser to rare medium a ray of light is?

• Undaviated
• Bent away from the normal
• Bent towards the normal
• Polarized

Question#5. Typical fibre optic communication system uses the light of which wavelength?

• 1.3μm
  
• 1.3nm
• 13μm
• 13nm

Question#6. The diamond shines due to:

• Interference
• Diffraction
• Scattering
• Total internal reflection

Question#7. If a lens is covered with wax then?

• Intensity becomes double
• The image will not formed
• Intensity will remain the same
• Intensity will become half

Question#8. The minimum distance between an object and its real image in a convex lens is:

• 2 f
• 2.5 f
• 3 f
• 4 f

Question#9. If an object is placed away from ‘2f’ of a converging lens, then the image will be?

• Real and erect
• Virtual and erect
• Real and inverted
• Virtual

Question#10. If the length of the telescope is 96cm the focal lengths of its lenses is:

• 100cm, -4cm
• -80cm, -6cm
• 90cm, -6cm
• 90cm, 6cm

Question#11. The magnifying power of a simple microscope:

• Increase with increase in focal length
• Increase with decrease in focal length
• No effect with decrease or increase with the focal length
• List distance of distinct vision

Question#12. Image of an object 5 mm high is only 1 cm high. Magnification produced by a lens is:

• 0.5
• 0.2
• 1
• 2

Question#13. The speed of light in the medium of the refractive index of 1.5 is?

• 2×10⁸ms^-1
• 3×10⁸ms^-1
• 0.5×10^8mms^-1
• 1.5×10⁸ms^-1

Question#14. Least distance of distinct vision of normal and healthy people:

• Increases with increase in age
• Decreases with increase in age
• Neither increases nor decreases
• Becomes infinite after 60 years

Question#15. In a convex lens of large aperture fails to converge the light rays incident on it to a single point, it is said to suffer from?

• Chromatic aberration
• Spherical aberration
• Both spherical and chromatic
• Distortion

Question#16. Two convex lenses of equal focal length ‘f’ are placed in contact, the resultant focal length of the combination is:

• Zero
• f
• 2 f
• f/2

Question#17. A convex length of focal length ‘f₁’ and concave lens of focal length ‘f₂’ are placed in contact. The focal length of the combination is:

•  f₂ + f₁
• f₂ – f₁
• f₁f₂  / f₂ + f₁
• -f₁f₂ / f₁ – f₂

Question#18. Final image produced by a compound microscope with respect to the object is?

• Real and inverted
• Real and erect
• Virtual and erect
• Virtual and inverted

Question#19. For normal adjustment, length of astronomical telescope is:

• f_o + f_e
• f_o – f_e
• f_o / f_e
• f_e / f_o

Question#20. A surfboard moves at an aped of 5ms^-1on the crests of the wave. The distance between wave crests is 10m. What is the frequency of the wave motion?

• 2 Hz
• 5 Hz
• 10 Hz
• 0.5 Hz

Question#21. Dispersion effect may produce an error in light signals. This type of error is minimum in:

• Single-mode step-index fiber
• Multimode step-index fiber
• Multimode graded-index fiber
• Monomode step-index fiber

Question#22. Light signals pass through multimode graded-index fiber due to?

• Continuous refraction
• Total internal reflection
• Both continuous refraction and total internal reflection
• Diffraction

Question#23. Which one type of fibre is more suitable for transmission of signals in which white light is used?

• Mono mode step-index fibre
• Multimode step-index fibre
• Multi-mode graded-index fibre
• Single-mode step-index fibre

Question#24. Critical angle is that incident angle in denser medium for which angle of refraction is.

• 0°
• 45°
• 90°
• 180°

Question#25. There is a noticeable boundary between core and cladding for?

• Multimode step-index fibre
• Multi-mode graded-index fibre
• Single-mode step-index fibre
• All types of fibre

Question#26. The electrical signals change into light signals for transmission through optical fibre. A light pulse represents.

• Zero (0)
• One (1)
• Both zero (0) and one (1)
• Either zero (0) or one (1)

Question#27. A lens, which is thicker at the center and thinner at the edges, is called?

• Concave lens
• Convex lens
• Plano-convex lens
• Plano concave lens

Question#28. A spectrometer is used to find?

• Wavelength flight
• Refractive index of the prism
• The wavelength of different colors
• All of the above

Question#29. If a convex lens of focal length ‘f’ is cut into two identical halves along the lens diameter, the focal length of each half is?

• f
• f/2
• 2f
  
• 3f/2

Question#30. A convex and concave lens of focal length ‘f’ are in contact. The focal length of the combination will be?

• Zero
• f/2
• 2f
• Infinite

Question#31. If the red light is replaced by blue light illuminating the object in a microscope the resolving power of the microscope?

• Increases
• Decreases
• Remain the same
• Become half

Question#32. In optic fiber transmission system __________ are used to regenerate the dim light signal.

• Diodes
• Repeaters
  
• Laser
• Transformer

Question#33. Magnification of the astronomical telescope is?

• f_o + f_e
• f_o / f_e
• f_e / f_o
• (1 + f_o/f_e) L/f_o

Question#34. The equation α_min = 1.22 λ/D was devised by?

• Newton
• Einstein
• Raleigh
  
• Planks

Question#35. The central image in a compound microscope is:

• Virtual, erect, and magnified
• Real, inverted, and smaller than object
• Virtual, erected and magnified
• Erect, virtual and smaller than final image

Question#36. Michelson calculated the speed of light using the instrument?

• Spectrometer
• Galvanometer
• Interferometer
• None of these

Question#37. Michelson devised the formula to calculate speed of light?

• c = 4fd
• c = 8fd
• c = 16fd
• c = 5/2 fd

Question#38. The function of collimator in spectrometer is?

• To produce parallel beam of light
• To filter the light rays
• To make them mutually perpendicular
• No function

Question#39. In optic fibre transmission, the repeaters are separated through a distance of _________ km in newer system.

• 300km
• 200km
• 100km
  
• 20km

Question#40. Which color has the maximum angle of deviation in prism?

• Red
• Blue
  
• Orange
• Green