SSC
Which type of mirror is used in solar cookers?
Answer (Detailed Solution Below)View answer ▾Hide ▴
Answer: Option B — Concave mirror
Detailed Solution
A concave mirror is a spherical mirror whose reflecting surface curves inwards, like the inside of a spoon. It is also called a converging mirror, because it reflects parallel rays of light so that they converge (come together) at a point called the principal focus, in front of the mirror.
In a solar cooker, a concave mirror (or a set of reflectors) is used to collect the parallel rays of sunlight falling on a large area and concentrate them at the focus. The cooking vessel is placed at or near the focus. Because a large amount of light energy is concentrated in a small area, a high temperature is produced, which can be used to cook food. Box-type solar cookers often use a plane mirror as a reflector along with a black box covered by a glass sheet, which traps heat through the greenhouse effect.
Other uses of concave mirrors:
- Shaving and make-up mirrors: when the face is placed between the focus and the mirror, an enlarged, erect, virtual image is formed.
- Dentists' mirrors: to see large images of teeth.
- Torches, car headlights and searchlights: the bulb is placed at the focus, so the reflected light goes out as a strong, parallel beam.
- Reflecting telescopes: to collect light from distant stars.
- Solar furnaces and solar power plants: to concentrate sunlight.
Convex mirrors, which curve outwards, always form diminished, erect, virtual images and give a wider field of view. They are used as rear-view (side-view) mirrors in vehicles, and in shops and at road bends for security and safety. Vehicle mirrors often carry the warning "Objects in mirror are closer than they appear".
Plane mirrors form images of the same size, erect and laterally inverted (left and right are reversed). They are used as looking glasses and in periscopes and kaleidoscopes.
Why not the other options?
- ✗Convex mirrors are used as rear-view mirrors in vehicles.
- ✗Plane mirrors are used as looking glasses and in periscopes.
- ✗Cylindrical convex mirrors are not used to concentrate sunlight.
Quick tip
Remember: Concave mirror = solar cookers, shaving mirrors, headlights, dentists, telescopes; convex mirror = rear-view mirrors (wider view); plane mirror = periscope, lateral inversion.
💬 Discussions on this question
Ask a doubt ›Still stuck on this question? Ask our faculty and fellow students — answers appear here.
Ask a doubtMore Light & Optics Questions
View all ›More General Knowledge Questions
- Q1.The techniques of Rasa and Bhava used in Indian classical dance trace their origin to which ancient text?Indian Dance Forms
- Q2.Lavani, Powada, Koli, Waghya Murali and Dhangari Gaja are folk dances of which state?Indian Dance Forms
- Q3.The one-act play associated with the Sattriya tradition of Assam is called:Indian Dance Forms
- Q4.Which dance form of Goa is known as the 'Warrior Dance'?Indian Dance Forms
- Q5.Manipuri dance is based on the Rasleela themes of:Indian Dance Forms
Light & Optics — Preparation
This question tests your understanding of Light & Optics, a key topic in the General Knowledge section. The detailed solution above uses a step-by-step approach to show the reasoning, and where available, a shortcut that helps you solve similar questions in under 90 seconds during the actual exam.
This topic covers the nature of light, reflection and refraction, mirrors and lenses, total internal reflection, dispersion and scattering of light, the human eye and its defects, optical instruments, and the colours of objects. Exams test the phenomena behind everyday sights: the sky looks blue because of the scattering of light, rainbows form through dispersion and internal reflection, diamonds sparkle because of total internal reflection, and mirages are caused by refraction. Know which lens corrects which defect (concave lenses for myopia and convex lenses for hypermetropia). Practise the light and optics questions below, written in the style of the general awareness sections of exams such as SSC, banking, railways, CUET GAT, MAH CET and CLAT. Each question comes with a detailed explanation that adds related facts, so every question helps you revise more than one point.