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An object 5 cm is placed at a distance of 20 cm in front of a convex mirror of radius of curvature 30 cm. Find the position, nature and size of the image.

Object distance (u) = – 20 cm Object height (h) = 5 cm Radius of curvature (R) = 30 cm... View Article

Name the type of mirror used in the following situations. (a) Headlights of a car (b) Side/rear-view mirror of a vehicle (c) Solar furnace Support your answer with reason.

Answer: A mirror is defined as a reflecting surface and can be explained by the law of reflection, which states... View Article

Why does the sky appear dark instead of blue to an astronaut?

The sky appears dark instead of blue to an astronaut, as a scattering of light does not take place outside... View Article

A person needs a lens of power -5.5 dioptres for correcting his distant vision. For correcting his near vision he needs a lens of power +1.5 dioptre. What is the focal length of the lens required for correcting (i) distant vision, and (ii) near vision?

The ability of the lens of the eye to adjust its focal length to clearly focus rays coming from distant... View Article

The least distance of distinct vision for a young adult with normal vision is about (a) 25 m (b) 2.5 cm (c) 25 cm (d) 2.5 m

The human eye forms an image of an object at its (a) cornea (b) iris (c) pupil (d) retina

(d) retina The retina is the layer of nerve cells lining the back wall inside the eye. This layer senses... View Article

he human eye can focus objects at different distances by adjusting the focal length of the eye lens. This is due to (a) presbyopia (b) accommodation (c) near-sightedness (d) far-sightedness

(a) Presbyopia A difficulty to see both nearby and far objects is called Presbyopia. Presbyopia is caused as part of... View Article

A student has difficulty reading the blackboard while sitting in the last row. What could be the defect the child is suffering from? How can it be corrected?

The student is suffering from short-sightedness or myopia. Myopia can be corrected by the use of a concave or diverging... View Article

What is the far point and near point of the human eye with normal vision?

Near Point The minimum distance of the object from the eye, which can be seen distinctly without strain is called the... View Article

A person with a myopic eye cannot see objects beyond 1.2 m distinctly. What should be the type of corrective lens used to restore proper vision?

An individual with a myopic eye should use a concave lens of focal length 1.2 m so that he or... View Article

List five things you have done over the last week to (a) conserve our natural resources. (b) increase the pressure on our natural resources.

Our environment comprises a wide variety of natural resources. Nowadays due to over utilisation we have exploited these natural resources.... View Article

How can you as an individual contribute or make a difference to the management of (a) forests and wildlife, (b) water resources and (c) coal and petroleum?

As an individual one should make the contribution and some variations for the management of Forests and wildlife, water resources... View Article

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Latest Posts

An object 5 cm is placed at a distance of 20 cm in front of a convex mirror of radius of curvature 30 cm. Find the position, nature and size of the image.

Name the type of mirror used in the following situations. (a) Headlights of a car (b) Side/rear-view mirror of a vehicle (c) Solar furnace Support your answer with reason.

Why does the sky appear dark instead of blue to an astronaut?

A person needs a lens of power -5.5 dioptres for correcting his distant vision. For correcting his near vision he needs a lens of power +1.5 dioptre. What is the focal length of the lens required for correcting (i) distant vision, and (ii) near vision?

The least distance of distinct vision for a young adult with normal vision is about (a) 25 m (b) 2.5 cm (c) 25 cm (d) 2.5 m

The human eye forms an image of an object at its (a) cornea (b) iris (c) pupil (d) retina

he human eye can focus objects at different distances by adjusting the focal length of the eye lens. This is due to (a) presbyopia (b) accommodation (c) near-sightedness (d) far-sightedness

A student has difficulty reading the blackboard while sitting in the last row. What could be the defect the child is suffering from? How can it be corrected?

What is the far point and near point of the human eye with normal vision?

A person with a myopic eye cannot see objects beyond 1.2 m distinctly. What should be the type of corrective lens used to restore proper vision?

List five things you have done over the last week to (a) conserve our natural resources. (b) increase the pressure on our natural resources.

How can you as an individual contribute or make a difference to the management of (a) forests and wildlife, (b) water resources and (c) coal and petroleum?

What changes would you suggest in your home in order to be environment-friendly?

Find out about the traditional systems of water harvesting/ management in your region.

Suggest some approaches towards the conservation of forests.

Compare and contrast bio-mass and hydroelectricity as sources of energy.

Compare and contrast fossil fuels and the sun as direct sources of energy.

Name two energy sources that you would consider to be renewable. Give reasons for your choices.

Hydrogen has been used as a rocket fuel. Would you consider it a cleaner fuel than CNG? Why or why not?

What is geothermal energy?