Class 10 Lenses Worksheet Maharashtra Board

Class 10 Science 1 Lenses Worksheet

The Class 10 Science 1 Chapter 7 Lenses Worksheet is designed according to the Maharashtra State Board syllabus. It provides focused practice for one of the most important optics chapters in the SSC Science 1 textbook. Students can use this worksheet to revise definitions, understand ray diagrams and practise numerical problems before their school tests and Maharashtra SSC Board examination.

The worksheet contains Maharashtra State Board exam important questions, MCQs, short-answer questions, diagram-based activities, application-based questions and selected previous board exam questions with their examination-year labels. It also works as an SSC question bank for students who want additional practice beyond the textbook exercises.

Questions cover the construction and working of convex and concave lenses, principal focus, optical centre, focal length, image formation, lens formula, magnification and power of a lens. Students also revise the human eye, myopia, hypermetropia, presbyopia and the lenses used to correct these vision defects.

What Is Included in This Worksheet?

• Multiple-choice questions based on lenses and refraction
• Fill in the blanks and match-the-column activities
• Definitions and scientific reasons
• Convex and concave lens ray diagrams
• Lens formula and magnification numericals
• Power of a lens and its SI unit
• Human eye and defects of vision
• Uses of lenses in daily life and optical instruments
• Maharashtra SSC Board important questions
• Selected previous board exam questions with year labels
• Answer key for checking practice

Important Concepts Covered

1. Convex and Concave Lenses

A convex lens is thicker at the centre and thinner near its edges. It generally converges parallel rays of light to a point and is therefore called a converging lens. A concave lens is thinner at the centre and thicker near its edges. It spreads parallel rays of light and is called a diverging lens.

2. Important Terms Related to a Lens

Students should understand the principal axis, optical centre, centre of curvature, principal focus, focal length and aperture of a lens. The optical centre is the point through which a ray of light passes without significant deviation. The distance between the optical centre and principal focus is called the focal length.

3. Standard Rays Used in Ray Diagrams

• A ray parallel to the principal axis passes through the principal focus after refraction through a convex lens.
• A ray passing through the principal focus emerges parallel to the principal axis.
• A ray passing through the optical centre travels almost undeviated.
• In a concave lens, a ray parallel to the principal axis appears to diverge from its principal focus.

4. Lens Formula

The lens formula gives the relationship between the focal length, image distance and object distance. Students must apply the Cartesian sign convention correctly before substituting values.

Here, f is the focal length, v is the image distance and u is the object distance. Distances measured in the direction of incident light are considered positive, while distances measured in the opposite direction are considered negative.

5. Magnification Produced by a Lens

Magnification compares the height of the image with the height of the object. A positive magnification indicates an erect image, while a negative magnification indicates an inverted image.

6. Power of a Lens

The focal length must be expressed in metres while calculating power. The SI unit of power is the dioptre, represented by D. A convex lens has positive power, whereas a concave lens has negative power.

Image Formation by Lenses

Convex Lens

The nature and position of the image formed by a convex lens depend on the position of the object. The image may be real or virtual, magnified or diminished, and erect or inverted. For example, when the object is beyond 2F, the image is formed between F and 2F. It is real, inverted and smaller than the object.

When the object is placed between F and the optical centre, the image formed is virtual, erect and magnified. This property is used in a magnifying glass.

Concave Lens

A concave lens always forms a virtual, erect and diminished image for a real object. The image appears between the principal focus and the optical centre on the same side as the object.

Human Eye and Vision Defects

Myopia

A person with myopia can see nearby objects clearly but cannot see distant objects clearly. The image of a distant object forms in front of the retina. Myopia is corrected using a concave lens.

Hypermetropia

A person with hypermetropia can see distant objects clearly but faces difficulty seeing nearby objects. The image of a nearby object would form behind the retina. A convex lens is used to correct this defect.

Presbyopia

Presbyopia commonly develops with increasing age because the eye lens loses flexibility and the eye muscles become weaker. A person may have difficulty focusing on nearby objects. Depending on the condition, convex lenses or bifocal lenses may be prescribed.

How to Draw a Correct Ray Diagram

1. Draw the principal axis using a ruler.
2. Draw the lens and mark its optical centre.
3. Mark F₁, F₂, 2F₁ and 2F₂ at equal and correct distances.
4. Place the object in the position given in the question.
5. Draw at least two standard rays from the top of the object.
6. Use arrowheads to show the direction of light.
7. Mark the point where the refracted rays meet or appear to meet.
8. State the position, size, orientation and nature of the image.

Common Mistakes Students Should Avoid