Class 8 Physical Science 100 Important MCQs
Class 8 Physical Science MCQs with Answers for TET DSC. Practice 100 important multiple choice questions for AP DSC, TS DSC, TRT, school exams and competitive exams.
1. What is the relation between the angle of incidence (i) and the angle of reflection (r)?
A) i > r
B) i < r
C) i = r
D) i + r = 90°
Answer: C
Explanation: According to the laws of reflection, the angle of incidence is always equal to the angle of reflection.
2. Reflection from a smooth surface like a mirror is called:
A) Diffused reflection
B) Regular reflection
C) Multiple reflection
D) Dispersion
Answer: B
Explanation: Reflection from a smooth surface like that of a mirror is called regular reflection, and images are formed by it.
3. The idea of the number of images formed by mirrors placed at an angle to one another is used in which of the following devices?
A) Periscope
B) Telescope
C) Microscope
D) Kaleidoscope
Answer: D
Explanation: This idea is used in a kaleidoscope to make numerous beautiful patterns.
4. The part of the eye which gives it its distinctive colour is:
A) Cornea
B) Pupil
C) Iris
D) Retina
Answer: C
Explanation: The iris is that part of the eye which gives it its distinctive colour and controls the amount of light entering the eye.
5. Which nerve cells in the retina are sensitive to bright light and sense colour?
A) Rods
B) Cones
C) Blind spot
D) Optic nerves
Answer: B
Explanation: Cones are sensitive to bright light and sense colour, whereas rods are sensitive to dim light.
6. The visually challenged person who developed the Braille system was:
A) Helen Keller
B) Louis Braille
C) Benjamin Franklin
D) Ravindra Jain
Answer: B
Explanation: Louis Braille, himself a visually challenged person, developed the system for visually challenged persons and published it in 1821.
7. Which of the following is a poor conductor of electricity?
A) Distilled water
B) Lemon juice
C) Tap water
D) Vinegar
Answer: A
Explanation: Distilled water is free of salts and is a poor conductor, whereas tap water contains dissolved salts making it a good conductor.
8. In an LED (Light Emitting Diode), the longer lead is always connected to which terminal of the battery?
A) Negative terminal
B) Positive terminal
C) Both terminals
D) Neutral
Answer: B
Explanation: The longer lead is always connected to the positive terminal of the battery and the shorter lead to the negative terminal.
9. In 1800, British chemist William Nicholson showed that passing an electric current through water produces bubbles of:
A) Oxygen and Carbon dioxide
B) Hydrogen and Nitrogen
C) Oxygen and Hydrogen
D) Nitrogen and Carbon dioxide
Answer: C
Explanation: He showed that if electrodes were immersed in water and a current was passed, bubbles of oxygen and hydrogen were produced.
10. The process of depositing a layer of any desired metal on another material by means of electricity is called:
A) Electrolysis
B) Electroplating
C) Electrotyping
D) Galvanisation
Answer: B
Explanation: This process is called electroplating, which is a common application of the chemical effects of electric current.
11. The impression of an image persists on the retina for about:
A) 1/10th of a second
B) 1/16th of a second
C) 1/20th of a second
D) 1/24th of a second
Answer: B
Explanation: The impression of an image does not vanish immediately from the retina; it persists there for about 1/16th of a second.
12. The splitting of white light into its constituent colours is known as:
A) Reflection
B) Refraction
C) Dispersion
D) Lateral inversion
Answer: C
Explanation: Splitting of light into its colours is known as dispersion of light. Rainbow is a natural phenomenon showing this.
13. If two plane mirrors are placed parallel to each other and a candle is placed between them, how many images are formed?
A) One
B) Two
C) Four
D) Infinite
Answer: D
Explanation: When two plane mirrors are set parallel to each other, an infinite number of multiple images are formed.
14. Tin cans used for storing food are made by electroplating tin onto iron because:
A) Tin is cheaper than iron
B) Tin is more reactive than iron
C) Tin is less reactive than iron
D) Iron is shiny
Answer: C
Explanation: Tin is less reactive than iron. Thus, food does not come into contact with iron and is protected from getting spoilt.
15. The most comfortable distance at which one can read with a normal eye is about:
A) 15 cm
B) 25 cm
C) 30 cm
D) 35 cm
Answer: B
Explanation: The most comfortable distance at which one can read with a normal eye is about 25 cm.
16. The outermost layer of the earth is fragmented into pieces. Each fragment is called a:
A) Core
B) Mantle
C) Plate
D) Pole
Answer: C
Explanation: The outermost layer of the earth is not in one piece. It is fragmented. Each fragment is called a plate.
17. A device used to protect buildings from the effect of lightning is:
A) Electroscope
B) Kaleidoscope
C) Lightning Conductor
D) Periscope
Answer: C
Explanation: Lightning Conductor is a device used to protect buildings from the effect of lightning.
18. When copper wires of a tester are inserted into a potato, a greenish-blue spot is observed around the wire connected to the:
A) Negative terminal
B) Positive terminal
C) Both terminals
D) Neither terminal
Answer: B
Explanation: The greenish-blue spot always forms around the wire connected to the positive terminal of the battery.
19. A device used to test whether an object is carrying an electric charge or not is called:
A) Kaleidoscope
B) Periscope
C) Electroscope
D) Microscope
Answer: C
Explanation: Such a device that can be used to test whether an object is carrying charge or not is known as an electroscope.
20. Lack of Vitamin A in the diet is responsible for many eye troubles, the most common being:
A) Cataract
B) Scurvy
C) Night blindness
D) Rickets
Answer: C
Explanation: Lack of vitamin A in foodstuff is responsible for many eye troubles. Most common amongst them is night blindness.
21. How many dot patterns or characters are there in the Braille system?
A) 61
B) 62
C) 63
D) 64
Answer: C
Explanation: The Braille system has 63 dot patterns or characters, where each character represents a letter, a combination of letters, a common word, or a grammatical sign.
22. Which metal is electroplated on iron to protect it from corrosion and rust in bridges and automobiles?
A) Copper
B) Zinc
C) Tin
D) Silver
Answer: B
Explanation: A coating of zinc is deposited on iron to protect it from corrosion and formation of rust.
23. The boundaries of the earth’s plates are the weak zones where earthquakes are more likely to occur. These are known as:
A) Danger zones
B) Seismic or fault zones
C) Crust zones
D) Mantle zones
Answer: B
Explanation: The boundaries of the plates are the weak zones where earthquakes are more likely to occur, and they are also known as seismic or fault zones.
24. To see well in the night, the owl has on its retina:
A) More cones and fewer rods
B) A large number of rods and only a few cones
C) Only cones and no rods
D) Equal number of rods and cones
Answer: B
Explanation: The owl has a large cornea and a large pupil, and on its retina, it has a large number of rods and only a few cones to see well in the dark.
25. The process of transferring an electric charge from a charged object to the earth is called:
A) Lightning
B) Electroplating
C) Earthing
D) Discharging
Answer: C
Explanation: The process of transferring charge from a charged object to the earth is called earthing, which protects us from electrical shocks.
26. In an image formed by a plane mirror, the left of the object appears on the right and the right appears on the left. This is known as:
A) Dispersion
B) Lateral inversion
C) Refraction
D) Regular reflection
Answer: B
Explanation: The phenomenon where the left of the object appears on the right and the right appears on the left in a mirror image is known as lateral inversion.
27. Which of the following is NOT a property of Chromium used in electroplating?
A) It has a shiny appearance
B) It does not corrode
C) It resists scratches
D) It is a very cheap metal
Answer: D
Explanation: Chromium has a shiny appearance, does not corrode, and resists scratches, but it is expensive.
28. In which year did the American scientist Benjamin Franklin show that lightning and the spark from clothes are essentially the same phenomena?
A) 1752
B) 1800
C) 1821
D) 1932
Answer: A
Explanation: In 1752, Benjamin Franklin showed that lightning and the spark from your clothes are essentially the same phenomena.
29. In old age, eyesight sometimes becomes foggy due to the eye lens becoming cloudy. This condition is called:
A) Night blindness
B) Cataract
C) Myopia
D) Blind spot
Answer: B
Explanation: When the eye lens becomes cloudy, it is said that the person has a cataract, causing a loss of vision.
30. What happens when two inflated balloons, both rubbed with a woollen cloth, are brought close to each other?
A) They attract each other
B) They repel each other
C) They burst
D) No interaction takes place
Answer: B
Explanation: Both balloons acquire the same kind of charge when rubbed with the woollen cloth, and objects with like charges repel each other.
31. Objects which shine in the light of other objects (like the Moon) are called:
A) Luminous objects
B) Illuminated objects
C) Transparent objects
D) Opaque objects
Answer: B
Explanation: Objects which shine in the light of other objects are called illuminated objects. The objects which emit their own light are luminous.
32. Movies that we see are actually separate pictures made to move across the eye usually at the rate of:
A) 16 pictures per second
B) 20 pictures per second
C) 24 pictures per second
D) 30 pictures per second
Answer: C
Explanation: They are made to move across the eye usually at the rate of 24 pictures per second (faster than 16 per second), so we see a moving picture.
33. Rainbow is a natural phenomenon showing:
A) Reflection
B) Dispersion
C) Lateral inversion
D) Regular reflection
Answer: B
Explanation: Splitting of light into its colours is known as dispersion of light. Rainbow is a natural phenomenon showing dispersion.
34. The transparent front part of the human eye is called:
A) Retina
B) Iris
C) Cornea
D) Lens
Answer: C
Explanation: The transparent front part of the eye is called the cornea.
35. The size of the pupil in the eye is controlled by:
A) Cornea
B) Lens
C) Iris
D) Optic nerve
Answer: C
Explanation: In the iris, there is a small opening called the pupil. The size of the pupil is controlled by the iris.
36. Pure or distilled water is a:
A) Good conductor of electricity
B) Poor conductor of electricity
C) Semiconductor
D) Superconductor
Answer: B
Explanation: Distilled water is free of salts and is a poor conductor.
37. Even if the electric current passing through a wire is small (weak), which effect can still be seen using a compass?
A) Heating effect
B) Chemical effect
C) Magnetic effect
D) Lighting effect
Answer: C
Explanation: Even if the current is small, the deflection of the magnetic needle can be seen due to the magnetic effect of currents.
38. What does LED stand for?
A) Light Emitting Diode
B) Light Energy Device
C) Low Energy Diode
D) Light Emission Detector
Answer: A
Explanation: LEDs stands for Light Emitting Diodes.
39. During William Nicholson’s experiment, oxygen bubbles were formed on the electrode connected to the:
A) Negative terminal
B) Positive terminal
C) Both terminals
D) Bottom of the beaker
Answer: B
Explanation: Oxygen bubbles formed on the electrode connected to the positive terminal of the battery and hydrogen bubbles formed on the other electrode.
40. The ancient Greeks knew as early as 600 B.C. that rubbing fur with ‘amber’ attracted light objects. What is amber?
A) A metal
B) A kind of resin
C) A type of glass
D) A magnetic stone
Answer: B
Explanation: The ancient Greeks knew as early as 600 B.C. that when amber (amber is a kind of resin) was rubbed with fur, it attracted light objects.
41. When a glass rod is rubbed with silk, the charge acquired by the glass rod is conventionally called:
A) Negative
B) Positive
C) Neutral
D) Magnetic
Answer: B
Explanation: It is a convention to call the charge acquired by a glass rod when it is rubbed with silk as positive.
42. Which of the following is true about electric charges?
A) Like charges attract each other
B) Unlike charges repel each other
C) Like charges repel each other
D) Charges do not interact
Answer: C
Explanation: Charges of the same kind (like charges) repel each other, while charges of different kind (unlike charges) attract each other.
43. The process of electric discharge between clouds or between clouds and the earth is called:
A) Earthing
B) Electroplating
C) Lightning
D) Reflection
Answer: C
Explanation: Negative and positive charges meet, producing streaks of bright light and sound. We see streaks as lightning. The process is called an electric discharge.
44. What is the safest position to take if you are in an open field with no shelter during a thunderstorm?
A) Lie flat on the ground
B) Stand under a tall tree
C) Squat low on the ground with hands on knees
D) Hold an umbrella
Answer: C
Explanation: Do not lie on the ground. Instead, squat low on the ground. Place your hands on your knees with your head between the hands. This makes you the smallest target.
45. The sudden shaking or trembling of the earth which lasts for a very short time is called:
A) Cyclone
B) Tsunami
C) Earthquake
D) Thunderstorm
Answer: C
Explanation: An earthquake is a sudden shaking or trembling of the earth which lasts for a very short time.
46. A major earthquake occurred in India in Bhuj district of Gujarat on:
A) 8 October 2005
B) 26 January 2001
C) 26 December 2004
D) 15 August 2003
Answer: B
Explanation: A major earthquake occurred on 26 January 2001 in Bhuj district of Gujarat.
47. The outermost layer of the earth where the disturbance causing an earthquake happens is called the:
A) Inner core
B) Outer core
C) Mantle
D) Crust
Answer: D
Explanation: Tremors are caused by the disturbance deep down inside the uppermost layer of the earth called the crust.
48. A major tsunami occurred in the Indian Ocean on:
A) 26 January 2001
B) 8 October 2005
C) 26 December 2004
D) 18 November 2002
Answer: C
Explanation: A major tsunami occurred in the Indian Ocean on 26 December 2004.
49. To protect iron from corrosion and rusting, it is usually electroplated with:
A) Copper
B) Zinc
C) Silver
D) Gold
Answer: B
Explanation: Iron tends to corrode and rust. So, a coating of zinc is deposited on iron to protect it from corrosion and formation of rust.
50. The famous book “The Story of my Life” (1903) was written by which visually challenged author?
A) Louis Braille
B) Helen A. Keller
C) Ravindra Jain
D) Lal Advani
Answer: B
Explanation: Helen A. Keller, an American author and lecturer, lost her sight when she was only 18 months old. She wrote a number of books including The Story of my Life (1903).
51. Which part of the eye acts as a screen where the image is formed?
A) Cornea
B) Iris
C) Pupil
D) Retina
Answer: D
Explanation: The lens focuses light on the back of the eye, on a layer called the retina.
52. The visually impaired singer who obtained a “Sangeet Prabhakar” degree from Allahabad is:
A) Diwakar
B) Lal Advani
C) Ravindra Jain
D) Louis Braille
Answer: C
Explanation: Ravindra Jain, born completely visually impaired, obtained his Sangeet Prabhakar degree from Allahabad.
53. When the free ends of a tester do not touch each other, there is an air gap. Air is generally a:
A) Good conductor of electricity
B) Poor conductor of electricity
C) Superconductor
D) Magnetic material
Answer: B
Explanation: Air is generally a poor conductor of electricity, but under certain conditions (like lightning), it allows current to pass.
54. What kind of metal is electroplated on cheaper metals by jewellery makers to make ornaments appear expensive?
A) Iron and Zinc
B) Copper and Tin
C) Silver and Gold
D) Aluminium and Lead
Answer: C
Explanation: Jewellery makers electroplate silver and gold on less expensive metals to give them the appearance of silver or gold.
55. In the blind spot of the human eye:
A) Only rods are present
B) Only cones are present
C) No sensory cells are present
D) Both rods and cones are maximum
Answer: C
Explanation: At the junction of the optic nerve and the retina, there are no sensory cells, so no vision is possible at that spot. This is called the blind spot.
56. The electric charge generated by rubbing two objects together (like a plastic scale on dry hair) is:
A) Alternating current
B) Static charge
C) Direct current
D) Magnetic charge
Answer: B
Explanation: The electrical charges generated by rubbing are static. They do not move by themselves.
57. During a thunderstorm, which of the following is SAFE to use?
A) Wired telephone
B) Cordless phone or Mobile phone
C) Running water for bathing
D) Open motorbike
Answer: B
Explanation: It is safer to use mobile phones and cordless phones because lightning can strike telephone cords.
58. The major earthquake that struck Uri and Tangdhar towns of North Kashmir occurred on:
A) 8 October 2005
B) 26 January 2001
C) 26 December 2004
D) 15 August 2000
Answer: A
Explanation: A major earthquake occurred in India on 8 October 2005 in Uri and Tangdhar towns of North Kashmir.
59. The device consisting of two or more mirrors used to see objects that are not directly in the line of sight (often used in submarines) is:
A) Kaleidoscope
B) Electroscope
C) Periscope
D) Microscope
Answer: C
Explanation: Periscopes are used in submarines, tanks, and also by soldiers in bunkers to see things outside. It makes use of two plane mirrors.
60. Which of the following liquids will NOT cause the magnetic needle of a tester to deflect?
A) Lemon juice
B) Tap water
C) Distilled water
D) Vinegar
Answer: C
Explanation: Distilled water is a poor conductor of electricity because it is free of salts. Hence, no current will flow, and the magnetic needle will not deflect.
61. Most liquids that conduct electricity are solutions of:
A) Acids only
B) Bases only
C) Salts only
D) Acids, bases, and salts
Answer: D
Explanation: Most liquids that conduct electricity are solutions of acids, bases, and salts.
62. The phenomenon of diffused or irregular reflection takes place when parallel rays strike a:
A) Smooth surface
B) Polished surface
C) Rough or irregular surface
D) Plane mirror
Answer: C
Explanation: When all the parallel rays reflected from a rough or irregular surface are not parallel, the reflection is known as diffused or irregular reflection.
63. In an electroplating process using copper sulphate, the free copper gets drawn to the electrode connected to the:
A) Positive terminal
B) Negative terminal
C) Both terminals
D) Bottom of the beaker
Answer: B
Explanation: The free copper gets drawn to the electrode connected to the negative terminal of the battery and gets deposited on it.
64. What part of the eye protects the interior of the eye from accidents and is tough and white?
A) Retina
B) Iris
C) Cornea
D) Optic nerve
Answer: C
Explanation: The outer coat of the eye is white and tough so that it can protect the interior. Its transparent front part is called the cornea.
65. Which of the following is NOT a chemical effect of electric current?
A) Formation of gas bubbles at electrodes
B) Deflection of a magnetic compass needle
C) Deposits of metal on electrodes
D) Change in colour of the solution
Answer: B
Explanation: Deflection of a magnetic compass is a magnetic effect, whereas bubbles, metal deposits, and colour changes are chemical effects.
66. What causes an earthquake?
A) Extreme heating of the earth’s surface
B) Movement of earth’s plates (crust)
C) Fast blowing winds
D) High tides in the ocean
Answer: B
Explanation: Tremors are caused by the disturbance deep down inside the uppermost layer of the earth called the crust, due to the movement of plates.
67. A child prodigy who was visually impaired but gave amazing performances as a singer in India is:
A) Lal Advani
B) Louis Braille
C) Diwakar
D) Helen Keller
Answer: C
Explanation: Diwakar, a child prodigy, has given amazing performances as a singer despite being visually impaired.
68. In the Braille system, dots are arranged in cells of:
A) Two vertical rows of two dots each
B) Two vertical rows of three dots each
C) Three vertical rows of two dots each
D) Three vertical rows of three dots each
Answer: B
Explanation: Dots are arranged in cells of two vertical rows of three dots each.
69. The second law of reflection states that the incident ray, the reflected ray, and the normal at the point of incidence:
A) Form a 90-degree angle
B) Are perpendicular to each other
C) Lie in the same plane
D) Are parallel to each other
Answer: C
Explanation: The incident ray, the normal at the point of incidence, and the reflected ray all lie in the same plane.
70. To detect weak electric currents, which of the following is most effective?
A) A regular electric bulb
B) An LED or a compass needle surrounded by wire
C) A plane mirror
D) A lightning conductor
Answer: B
Explanation: A weak current may not heat a bulb’s filament enough to glow, but it can make an LED glow or deflect a magnetic compass needle.
71. Foods rich in Vitamin A, which are essential for good eye health, include:
A) Raw carrots, broccoli, and spinach
B) Rice, potatoes, and wheat
C) Sugar, salt, and vinegar
D) Coffee, tea, and soft drinks
Answer: A
Explanation: Raw carrots, broccoli, green vegetables (such as spinach), and cod liver oil are rich in vitamin A.
72. When rubbing a used ballpen refill with polythene, what happens to the objects?
A) Only the refill gets charged
B) Only the polythene gets charged
C) Both the refill and polythene get charged
D) Neither gets charged
Answer: C
Explanation: In the process of charging the refill and the plastic comb, polythene and hair also get charged.
73. The transfer of charge from a charged body to the earth is practically useful for:
A) Charging batteries
B) Electroplating metals
C) Protecting buildings from electrical shocks due to current leakage
D) Generating lightning
Answer: C
Explanation: Earthing is provided in buildings to protect us from electrical shocks due to any leakage of electrical current.
74. During a thunderstorm, if you are in a forest, you should take shelter under:
A) The tallest tree
B) Shorter trees
C) Metal poles
D) An umbrella
Answer: B
Explanation: If in a forest, take shelter under shorter trees as tall trees are more likely to be struck by lightning.
75. If the angle of incidence is 40°, what will be the angle between the incident ray and the reflected ray?
A) 40°
B) 50°
C) 80°
D) 90°
Answer: C
Explanation: According to the law of reflection, angle of reflection = 40°. The total angle between incident and reflected ray = 40° + 40° = 80°.
76. The Indian visually impaired person who represented India on Braille problems in UNESCO is:
A) Diwakar
B) Ravindra Jain
C) Lal Advani
D) Louis Braille
Answer: C
Explanation: Lal Advani, himself visually impaired, established an Association for special education… Besides this, he represented India on Braille problems in UNESCO.
77. Eye donation can be done by a person suffering from which of the following conditions?
A) Normal diseases like diabetes or hypertension (using spectacles)
B) AIDS
C) Rabies
D) Cholera
Answer: A
Explanation: Eyes can be donated by a person of any age, using spectacles, or suffering from normal diseases, but NOT AIDS, rabies, cholera, etc.
78. After the death of a person, within how many hours should the eyes be donated?
A) 1-2 hours
B) 4-6 hours
C) 12-24 hours
D) 48 hours
Answer: B
Explanation: The eyes have to be donated within 4-6 hours after death at any place, home or hospital.
79. An image formed by a plane mirror is always:
A) Real, inverted, and smaller
B) Virtual, erect, and of the same size
C) Virtual, inverted, and larger
D) Real, erect, and of the same size
Answer: B
Explanation: Image formed by a plane mirror is virtual, behind the mirror, erect, and of the same size as the object.
80. The phenomenon of the accumulation of charges in clouds leading to bright streaks of light is known as:
A) Earthquakes
B) Tsunamis
C) Lightning
D) Electroplating
Answer: C
Explanation: Accumulation of charges in clouds leads to the phenomenon we understand as lightning.
81. The process by which water is separated into hydrogen and oxygen using an electric current is due to the:
A) Magnetic effect of electric current
B) Heating effect of electric current
C) Chemical effect of electric current
D) Lighting effect of electric current
Answer: C
Explanation: Passing current through water causing bubbles of oxygen and hydrogen is a prime example of the chemical effect of electric current.
82. Why do designers of wallpapers and fabrics use kaleidoscopes?
A) To test electric currents
B) To get ideas for new and unique patterns
C) To protect buildings from lightning
D) To measure angles of reflection
Answer: B
Explanation: Designers of wallpapers and fabrics and artists often use kaleidoscopes to get ideas for new patterns, as it never shows the same pattern again.
83. An earthquake occurring under the ocean can primarily cause a:
A) Thunderstorm
B) Tsunami
C) Lightning strike
D) Tornado
Answer: B
Explanation: Earthquakes can cause floods, landslides, and tsunamis. A major tsunami occurred in the Indian Ocean in 2004.
84. In India, which of the following areas is NOT typically considered a highly threatened seismic (fault) zone?
A) Kashmir
B) Rann of Kutch
C) North-East region
D) Most parts of Central Deccan Plateau
Answer: D
Explanation: The most threatened areas are Kashmir, Himalayas, North-East, Rann of Kutch, Rajasthan, and the Indo-Gangetic Plane. Only some areas of South India fall in the danger zone.
85. If you are travelling by car during a thunderstorm, how can you keep yourself safe?
A) Stand on the roof of the car
B) Keep the windows and doors of the car shut
C) Open all the windows
D) Lie under the car
Answer: B
Explanation: If you are travelling by car or by bus, you are safe inside with windows and doors of the vehicle shut.
86. When the current through a circuit is too weak, the bulb does not glow because:
A) The filament breaks
B) The filament does not get heated sufficiently
C) The bulb is a poor conductor
D) Magnetic effect cancels the current
Answer: B
Explanation: If the current through a circuit is too weak, the filament does not get heated sufficiently and it does not glow.
87. Which part of the eye carries sensations from the retina to the brain?
A) Iris
B) Cornea
C) Pupil
D) Optic nerve
Answer: D
Explanation: Sensations felt by the nerve cells on the retina are transmitted to the brain through the optic nerve.
88. A night bird like an owl can see well in the night because it has a:
A) Small cornea and small pupil
B) Large cornea and large pupil
C) Large cornea but no pupil
D) No cornea at all
Answer: B
Explanation: The owl has a large cornea and a large pupil to allow more light in its eye.
89. What type of reflection takes place when a beam of light strikes a polished wooden table?
A) Regular reflection
B) Irregular/Diffused reflection
C) Multiple reflection
D) No reflection
Answer: A
Explanation: A polished surface acts like a mirror, so regular reflection will take place.
90. If you touch a charged electroscope with your hand, the foil strips:
A) Spread further apart
B) Start vibrating
C) Collapse (come back to original state)
D) Produce a spark
Answer: C
Explanation: The foil strips collapse as soon as you touch the paperclip with your hand because the charge flows to the earth through your body (earthing).
91. The outer layer of the Earth, which is fragmented into plates, is known as the:
A) Mantle
B) Inner core
C) Outer core
D) Crust
Answer: D
Explanation: The outermost layer of the earth is the crust, and it is fragmented into plates.
92. Which of the following objects will be attracted by a plastic scale rubbed on dry hair?
A) A heavy iron nail
B) Very small pieces of paper
C) A glass tumbler
D) A wooden block
Answer: B
Explanation: When you rub a plastic scale on your dry hair, the scale acquires a static charge and can attract very small pieces of paper.
93. In the context of the eye, what is the function of the lens?
A) It controls the amount of light entering the eye
B) It protects the inner eye
C) It focuses light on the back of the eye (retina)
D) It senses colors
Answer: C
Explanation: The lens focuses light on the back of the eye, on a layer called the retina.
94. Which of the following is an auditory aid for the visually impaired?
A) Magnifiers
B) Braille writer slate
C) Contact lenses
D) Talking books and tape recorders
Answer: D
Explanation: Auditory aids include cassettes, tape recorders, talking books, and other such devices using the sense of hearing.
95. During electroplating of copper on a material, what happens to the copper plate connected to the positive terminal?
A) It gains copper
B) It dissolves into the solution
C) It remains unchanged
D) It produces oxygen gas
Answer: B
Explanation: From the other electrode (connected to the positive terminal), an equal amount of copper gets dissolved into the solution to restore the loss.
96. What causes the static electric charges generated by rubbing two bodies?
A) Earthing
B) Heating
C) Friction (rubbing)
D) Lightning
Answer: C
Explanation: The electrical charges generated by rubbing (friction) are static.
97. If the angle between the incident ray and the plane mirror is 30°, what is the angle of reflection?
A) 30°
B) 60°
C) 90°
D) 120°
Answer: B
Explanation: The angle of incidence is the angle between the normal and the incident ray. Normal is 90° to the mirror. So, angle of incidence i = 90° – 30° = 60°. According to the law of reflection, angle of reflection r = i = 60°.
98. Which of the following is NOT true about an earthquake?
A) It can cause tsunamis and landslides
B) It can be predicted accurately days in advance
C) It is caused by the movement of tectonic plates
D) It causes shaking of the earth
Answer: B
Explanation: Although we know what causes an earthquake, it is not yet possible to predict when and where the next earthquake might occur accurately.
99. A visual aid (optical aid) for visually impaired people includes:
A) Braille slate
B) Talking calculator
C) Bifocal lenses and magnifiers
D) Audio CD
Answer: C
Explanation: Optical aids include bifocal lenses, contact lenses, tinted lenses, magnifiers, and telescopic aids.
100. The phenomenon of electrical discharge between the clouds and the earth is accompanied by streaks of bright light and sound. What is the sound called?
A) Tsunami
B) Tremor
C) Thunder
D) Dispersion
Answer: C
Explanation: Negative and positive charges meet, producing streaks of bright light (lightning) and sound (thunder).
