Everyday Science Short Questions And Entry Test Preparation Resources
These Everyday Science Short Questions With Answers are highly useful for preparing Cadet College Entry Tests, Defence Forces Tests, and Competitive Examinations. These questions help students understand basic concepts of Everyday Science and improve their preparation.
Explore more Everyday Science Notes, MCQs, Past Papers, and Admission Preparation Resources through the following links.
Everyday Science Short Questions And Answers Part 1
Important Everyday Science Short Questions With Answers for students preparing Cadet College Entry Tests, Defence Forces Tests, Army, Navy, PAF, and Competitive Examinations. These notes help students understand basic science concepts and improve their test preparation.
Q. Define Radiation And Explain How Heat Is Transferred By Radiation?
Radiation:
The transfer of heat energy from a hot body to a cold body directly, without heating the space between the two bodies, is called radiation.
Explanation:
The heat from the sun reaches us by radiation. Air is a bad conductor, so conduction and convection cannot transfer the sun's heat to the earth. Radiation does not require any medium for heat transfer.
Q. What Are Good And Bad Radiators And Absorbers Of Heat?
- Black Surfaces: Black surfaces are good absorbers and suitable radiators of heat.
- Shiny Surfaces: Shiny surfaces are bad absorbers and bad radiators of heat.
Q. What Is The Application Of Radiation Of Heat?
Everyday Application Of Radiation Of Heat:
Every object emits or radiates some amount of heat. Knowledge of radiation helps us in many daily life applications.
Warming Body Near Fire:
When we sit beside a fire, the heat reaches us through radiation. It does not warm the air between us and the fire.
Cooling In A Cooling Machine:
Cooling fans at the back of refrigerators radiate heat quickly to the surroundings. Their surfaces are made rough and painted black.
Wear Light Colours In Summer:
White or light-coloured clothes absorb less heat than dark colours, so they are preferred during hot summer days.
Use Of Greenhouse:
In cold areas, greenhouses are used for better plant growth. Radiation from the sun passes through glass or plastic and increases the temperature inside.
Q. What Is A Vacuum Flask? How Does It Work?
Vacuum Flask:
A container that keeps hot things hot and cold things cold is called a vacuum flask.
Structure Of Vacuum Flask:
A vacuum flask consists of two thin glass or metal bottles. The air between the walls is removed to create a vacuum. The walls are coated with aluminium to reduce heat transfer by radiation. The mouth is made from poor conductors such as cork or plastic to reduce heat loss.
Q. Metals Are Good Conductors Of Heat; Why?
Particles of metals are closely packed, so one particle easily transfers heat to another. Metals also contain free electrons that help in faster heat transfer.
Q. Define And Explain Refraction?
Refraction:
When light travels from one transparent medium to another, its speed and direction change. This change in direction of light is called refraction.
Condition:
When light falls perpendicular to the surface of a medium, it does not change its direction.
Q. In What Direction Does A Ray Bend While Passing Through Different Mediums?
Light Ray From Air To Water:
When light passes from air to water or glass, it bends towards the normal. The angle of incidence is greater than the angle of refraction.
Light Ray From Glass To Air:
When light passes from water or glass to air, it bends away from the normal.
Everyday Science Short Questions And Answers Part 2
Important Everyday Science Short Questions And Answers for Cadet College Entry Tests, Defence Forces Examinations, Army, Navy, PAF, and Competitive Tests. These science notes help students understand important concepts of light, refraction, and optical instruments.
Q. Discuss The Effects Of Refraction?
Effects Of Refraction:
- Whenever we open our eyes, we observe the refraction of light.
- The lens in our eye refracts light to form an image on the retina.
- A pencil placed in water appears broken due to the refraction of light.
- Refraction causes the formation of rainbows.
- Refraction occurs in lenses used in spectacles, telescopes, and magnifying glasses.
Q. Define Incident Ray, Refracted Ray, Normal, Angle Of Incidence And Angle Of Refraction?
Incident Ray:
The ray of light that falls on the surface of another medium is called an incident ray.
Refracted Ray:
The ray of light that changes its direction while entering another medium is called a refracted ray.
Normal:
An imaginary line drawn perpendicular to the surface of the medium at the point of incidence is called normal.
Angle Of Incidence:
The angle between the normal and incident ray is called the angle of incidence.
Angle Of Refraction:
The angle between the normal and refracted ray is called the angle of refraction.
Q. Define Refractive Index And Write Its Formula?
Refractive Index:
The degree to which a medium can bend light is called its refractive index. It is the ratio of the speed of light in vacuum to its speed in the medium.
Formula: Refractive Index = Speed Of Light In Vacuum / Speed Of Light In Medium
Q. Why Are Real And Apparent Depths Different?
Refraction of light gives us a false impression about the depth and position of objects in water or glass. Swimming pools appear shallower because light bends away from the normal when it travels from water to air.
Q. Define Critical Angle?
When the angle of refraction becomes 90° due to increasing angle of incidence, this stage is called the critical angle.
The critical angle is represented by C°. The critical angle of water is about 49° and glass is about 42°.
Q. Write Down The Laws Of Refraction And Give Its Equation?
Laws Of Refraction:
- The incident ray, refracted ray, and normal all lie in the same plane.
- For two particular mediums, the ratio of sine of angle of incidence to sine of angle of refraction remains constant.
Q. Define Total Internal Reflection?
Total Internal Reflection:
When the angle of incidence is greater than the critical angle, light rays reflect back into the same denser medium. This phenomenon is called total internal reflection.
Conditions Of Total Internal Reflection:
- Light must travel from a denser medium to a rarer medium.
- The angle of incidence must be greater than the critical angle.
Q. What Is The Application Of Total Internal Reflection?
Total internal reflection is used in optical instruments such as prisms, binoculars, periscopes, mirages, and fish-eye views.
Q. What Is A Prism?
A prism is a glass block with three rectangular and two triangular surfaces. A right-angled prism has one 90° angle and two 45° angles. It works on the principle of total internal reflection.
Q. Which Prism And Principle Are Used To Make Binoculars?
Binoculars use right-angled reflection prisms. When light enters the prism at an angle greater than the critical angle, total internal reflection occurs and distant objects can be viewed clearly.
Q. Explain The Structure Of The Periscope?
Structure:
A simple periscope consists of a tube with two right-angled prisms fitted at both ends. The first prism turns light towards the second prism, which reflects it towards the observer's eye.
Principle:
A periscope works on the principle of total internal reflection.
Uses:
- Periscopes are used in submarines.
- Periscopes are used in tanks and other military equipment.
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